Calendula officinalis

PEST

   NAME

     Budworms

     Helicoverpa species

   ORDER

     Lepidoptera

   FAMILY

     Noctuidae

Description of the Pest

Mature larvae are caterpillars up to 45 mm long; colour varies from yellowish-green to reddish-brown, most with stripes or darker body markings. Female moths have a wingspan up to 40 mm across, are reddish brown in colour; hindwings are pale at the base and dark along the edges.

Moths of Heliothis are very similar to that Helicoverpa armigera (Corn earworm).

Helicoverpa have a spot which is kidney shaped in the centre of the forewing,

The Adults of all species are attracted to lights at night.

                 

The larvae are smooth and vary in colour but have light coloured strips

Life Cycle

This insect has a Holometabolous life cycle, i.e. it has a larval and a pupal stage.

Females lay up to 1000 tiny white eggs, deposited singly, on the young growth of host plants.

Larvae pupate in the topsoil, after feeding for 2-3 weeks; the emergence of adults is triggered by appropriate moisture & temperature conditions during Spring. Long periods of cold and drought can delay the emergence of the adult moths for up to 5 months.

There are two main periods of infestation early summer and autumn.

Distribution of the Pest

Helicoverpa species (Heliothis species) are found throughout Australia.

Larvae have prominent prolegs

Period of Activity

Most active in Spring and Summer, after good rainfall and vigorous plant growth.

Damage Caused

Larvae attack chew on new growth, fruit, seed and flower buds. Fruit and flowers are damaged and yield is reduced. Entry holes in fruit enlarge and become more obvious as the caterpillar matures.

Bud worms which feed inside the flower buds can cause the buds to brown and not open.

Damage to a flower bud

Susceptible Plants

Attacks a wide range of fruiting and ornamentals plants, such as gardenias, carnations, roses, calendula, hollyhocks, snapdragons, etc. This is a major pest of commercially grown tomatoes, beans,

sweet corn, cotton, sorghum and peas.

Pseudotsuga menziesii, Picea, Pinus, Pseudolarix and Tsuga species are attacked by the Spruce Budworm (Choristoneura fumiferana). Symptoms include the new opening buds and needles are eaten by the dark red caterpillar that has a yellow stripe along its side. It is a serious pest to ornamental and forest trees and control is difficult.

Control

Cultural Control

It is difficult to control bud-worms once they enter the fruit or buds so it important to apply clay and pepper sprays or pyrethrum, while the young lava are feeding on the leaves.  Caterpillars may be removed by hand or infested flowers and fruit removed from the plant.

Biological Control

Genetically modified crops have been developed for cotton.

A virus NPV may be commercially available for cotton growers to control Helicoverpa armigera and H punctigera

Helicoverpa armigera & Helicoverpa punctigera), are parasitised by many different insects, including Chaetophthalmus dorsalis flies from the Tachinidae family.

Egg parasites include Trichogramma & Telenomus wasps

Larval parasites include         Micrropilitis demolitor, Netelia producta and Trachnid flies

Larval pupa parasites include Heteropelma scaposum and Lissopimpla excelsa

Pupal parasites include Ichneumon promissorius

Chemical Control

Control needs to occur before the larvae enter the fruit or flowers.

Note

It is your responsibility by law to read & follow the directions on the label of any pesticide

Monitoring

Shake plants twice a week on to a stiff white cardboard, once they start flowering.

Other Common Names; includes

Native Budworm (Helicoverpa punctigera) Tomato grub, Cotton bollworm, Corn ear worm, Tobacco budworm

Amendments by B. Sonsie Dip Hort Sc Burnley

PEST

   NAME

     Looper Caterpillars

     Various Looper Caterpillar Species

   ORDER

     Lepidoptera

   FAMILY

     Noctuidae

Description of the Pest

The looper is so-called because of the larvae's characteristic "looping" movement: the back legs move forward behind the front legs, causing the body to arch into an inverted "U" shape. They vary in colour and size; Brown Looper (Lophodes sinistraria) can grow to 50mm long, glossy black with yellowish bands then maturing to brown and found in coastal sub-tropical regions.

Green Wattle Looper (Thalaina species) adult is a small white moth with a wing span of 40mm and the lava is a slender green caterpillar with a rounded head. It is commonly found on ferny leaves Acacia species and when it is not feeding it takes up an erect position imitating a twig growing at an angle. It is difficult to detect and normally not requiring control.

Grevillea Lopper (Oenochroma vinaria) is a slender caterpillar that is greyish with orange bands and has two thorn-like projections on its back towards the head that it uses in a defence position. It is hairless with mottled orange colouring and grows to 80mm long.  The adult moth (pink belly moth) has a wing span up to 60mm across and is pinkish.

Brown Looper (Lophodes sinistraria) are black with yellowish bands at first maturing to brown growing to 50mm long. It is a solitary feeder eating mature leaves and are found in tropical to sub tropical regions.

Appearance and Distribution of the Pest

Many species are found throughout Australia from tropical to temperate regions.

                 

Life Cycle

These insects have a Holometabolous life cycle, ie. When metamorphosis is observed during the pupal stage.

Period of Activity

Most active during the warmer months the larva feed generally in the early morning or in the evening. Caterpillars are also active during cloudy days.

Damage Caused

Larvae are voracious feeders, skeletonising leaves or stripping them to the midrib preferring new growth.. Certain species feed solitary while others in groups.

The Grevillea Lopper feeds solitary or in groups defoliating small areas in species such as Lambertia and Grevillea.  

                 

Susceptible Plants

A wide range of native and exotic plants are attacked, depending on the species of looper. Plants with soft-textured foliage (eg vegetables, some indoor plants) are preferred.  The Brown Looper is found on Acmena smithii, Waterhousea floribunda and Macadamia species.

Tropaeolum and Calendula species are attacked by the Cabbage Looper (Trichoplusia ni), which feeds on the leaves and flowers.Tropaeolum species are also attacked by the caterpillar (Pieris rapae), which eats the foliage.

Cultural Control

Small numbers may be removed by hand.

Biological Control

Birds and other predators reduce numbers.

Chemical Control

The plant may be sprayed using Carbaryl. During heavy infestations this method is effective.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

PEST

   NAME

     Aphids

     Various Aphid Species

   ORDER

     Hemiptera

   FAMILY

     Aphididae

Description of the Pest

The common name varies and aphids may be referred to as black fly, greenfly, ant cows or plant lice.

These small insects have soft globular body that is from 1mm to 8mm long and vary in colour from green, yellow, black and pink, with the winged forms being elongated. Both adult and nymphs, have piercing and sucking mouthparts.

Aphids are found on buds, flowers, or leaves and stems, preferring soft new growth. On older leaves the aphids are found in protected positions, such as under the leaf. Certain species of aphids form galls as they suck sap and may be found on the roots of the plant. (E.g. Woolly aphids and Black peach aphids)

Most aphids possess a pair of characteristic tubular projections, known as cornicles; these secrete a pheromone and a waxy fluid, which is thought to protect them from some of their predacious enemies.

White exoskeletons, honey dew and sooty mould indicate the presence of Aphids

Balsam Twig Aphid (Mindarus abietinus) is greenish and covered in a white wax and is normally found on the young shoots of conifers bending and killing the needles. It is found on Abies and Picea species.

Aphid and their exoskeletons    on underside of a leaf

Black Citrus Aphid (Toxoptera aurantii) has a soft plump green body and the black coloured adults may or may not be winged. They feed in groups, curling leaves and producing honeydew attracting sooty mould.

Green Peach Aphid (Myzus persicae) is a soft plump green insect up to 0.2mm long and may be wingless. The nymphs are yellowish green and are responsible for spreading viruses in Dianthus species.

Spruce Gall Aphid (Chermes abietis) form cone shaped galls up to 12mm long resulting from the feeding. The wingless female adult lays eggs on the stems and the immature females overwinter on bud scales. Large infestation will weaken trees such as Picea abies and Pseudotsuga menziesii.

Tulip Bulb Aphid (Anuraphis tulipae) is small, waxy grey coloured and infests the underside of the bulb scales or rhizomes. They occur in the ground or on above ground parts and during storage.

Life Cycle

These insects have a Hemimetabolous life cycle, i.e. The nymphs resemble the adults.

During spring all eggs produced hatch as female nymphs. Adult Aphids are capable reproducing without fertilisation.  The males are only produced in some species as the weather cools down, and the day length shortens.

Aphids are capable of giving birth to living young and large populations build up quickly during summer. Over crowding causes the aphids to become smaller, less fertile and produce more winged forms that can migrate to other host plants.

There are many different types of aphids and the life cycle varies from warm to cold climates.

Typical life cycles

Distribution of the Pest

World wide

Period of Activity

In warm climates they are seen throughout the year, but aphids dislike hot dry or cold conditions and heavy rain will decrease the population. In cold areas aphid eggs are laid around a bud base or other protected areas of the plant during autumn and emerge as nymphs during spring, feeding on the new growth.

Numbers build up quickly in the warmer months of the year. Some species feed during winter on Sow thistles.

Susceptible Plants

There is a wide range of plants attacked, from roses to vegetables, shrubs and trees. Certain aphids attack a specific genus while others have a wide range of host plants. Many are capable of transmitting plant virus diseases.

Adults and nymphs feeding    A colony of aphids

Acer species are attacked by several aphids including the Norway Maple Aphid (Periphyllus lyropictus) which is a greenish with brown markings and secret honeydew, preferring Acer platanoides. Other aphids include (Drepanaphis acerifolia) and (Periphyllus aceris) which are commonly found on the underside of leaves.

Acer species are also attacked by the Woolly Maple Aphid (Phenacoccus acericola) which covers the undersides of the leaves with a cotton-like mass

Alnus species are infested with the Alder Blight Aphid (Prociphilus tessellates) which is blue-black adult that forms woolly masses on the down-turned leaves. The nymphs overwinter in bark crevices.

Aquilegia species are attacked by several aphids including (Pergandeidia trirhoda) which is a small, flat cream coloured insect that is found on young branches and the underside of leaves.

Betula species may be attacked by the European Birch Aphid (Euceraphis betulae) which is small and yellowish or the Common Birch Aphid (Calaphis betulaecolens) which is large and green producing ample honeydew for sooty mold to grow on.

Callistephus species may be attacked by the Corn Root Aphid (Anuraphis maidi-radicis) causing the plant to become stunted, the leaves wilt and turn yellow. The aphids feed on the roots producing honeydew and are dispersed to other host by ants. It is also attacked by the Potato Aphid (Macrosiphum solanifolii).

Carya species are attacked by Gall Aphids (Phylloxera caryaecaulis) which is found on the leaves, twigs and stems forming galls and turning them black.

Chaenomeles and Gladiolus species, new growth and leaves become infested with the aphid (Aphis Gossypii)

Cupressus macrocarpa may become infested with the Cypress Aphid (Siphonartrophia cupressi).

Cyclamen species are attacked by the aphid (Myzus circumflexus) and (Aphis gossypii) which can infest healthy plants.

Dendranthema, Dianthus  and Crocus species are attacked by several types of aphid including the Green Peach Aphid (Myzus persicae) and the Chrysanthemum Aphid (Macrosiphoniella sanborni).

Hibiscus species are attacked by the aphids (Aphis craccivora)  and (Aphis gossypii), both congregate towards the branch tips and may cause leaf curl. Normally only seen in sub-tropical climates.

Aphids on a stem    Mandevilla species

Larix species is attacked by the Woolly Larch Aphid (Adelges strobilobius). The winged adults deposit eggs at the base of the needles during spring and white woolly areas appear attached to the needles where the adult aphids feed. The young aphids overwinter in the crevices of the bark.

Mandevilla species is attacked by aphids that congregate towards the branch tips and may cause leaf curl.

Pinus species is attacked by several species of aphid including Pine Bark Aphid (Pineus strobi), Pine leaf Aphid (Pineus pinifoliae) and the White Pine Aphid (Cinara strobi).

Primula species are attacked by four species of aphid including foxglove, and green peach aphid.

Rudbeckia, Delphinium, Chrysanthemum and Helianthus species are attacked by a bright red aphid (Macrosiphum rudbeckiae).

Sorbus aucuparia is affected by the Rosy Apple and Woolly Apple aphid which attacked the foliage and young shoots.

Spiraea species are attacked by the Aphid (Aphis spiraecola) which feeds on the young shoots and flowers.

Tropaeolum species are attacked by the Black Bean Aphid (Aphis fabae), which is found in large numbers on the underside of the leaves, turning them yellow and causing them to wilt then die.

Tulipa, Iris, Freesia, Gladiolus and Zephyranthes species are infested with the Tulip Bulb Aphid.

Ulmus species are infected by two types the Woolly Apple Aphid (Eriosoma lanigerum), which curls and kills young terminal leaves and the Elm Leaf-Curl Aphid (Eriosoma ulmi) which occasionally attacks the trees.

Viburnum species are attacked by the Snowball Aphid (Anuraphis viburnicola). This aphid congregates at the end of the branches causing the leaves to curl and become deformed under which they hide.

Aphids on Quercus robur

Damage Caused

Buds that have been attacked may not open, leaves and twigs become twisted or distorted and wilt. The aphids also produce honeydew, which is sticky and attracts sooty mould (fungus). This fungus forms a thick layer over the leaf, fruit or stems reducing the plants photosynthesis capability. The sooty mould spoils the plants appearance and its fruit, as does the insects white exoskeletons.

Control

Cultural Control

Aphids may be removed from a plant by hosing them off with water (limited success) or applying soapy water to aphids.. Another organic sprays can be efficient in controlling aphids. Aphids  may also be removed physically by hand for small colonies on spine less plants. Species that live under ground are difficult to control but cultivation of the surrounding soil may help in controlling the infestation. (limited mainly to annual or commercial crops)

Reflective mulch around the plants also reduces numbers by repelling the insect this material is available commercially. (Reflective mulches are mainly used in market gardens for avoiding the Green peach Aphids) Resistant rootstocks are available to avoid some root feeding aphid of commercial plants, e.g. Vines and fruit trees

Biological control

Aphids are attacked by several insects includes parasitic wasps or predators such as ladybirds/ lady beetles, hover flies, lacewings, spiders.

   Parasitised aphids

Chemical Control

Aphids may be controlled by spraying with a contact or systemic insecticide. The type of application used will depend on the plant is being attacked.

Aphids can be suffocated and therefore controlled with the use of e.g. White oil, Pest oil, Soapy water from soap such as Lux Flakes ®

Note

It is your responsibility by law to read & follow the directions on the label of any pesticide

Monitoring

Aphid are attracted by yellow colour and traps such as boards painted yellow and covered in glue or sticky substance will attract and trap the insects.  There is also a commercially sticky yellow tape that can be attached to susceptible plants

Amendments by B. Sonsie Dip Hort Sc Burnley

PEST

   NAME

     Leafminer (General)

     Various Leafminer Species

Description of the Pest

There is a wide range of insects that have larvae, which mine leaves and these are found throughout the world. These include beetles, wasps, sawflies, moths and flies. The larvae may or may-not have legs, but are normally flattened.

These insects have a Holometabolous life cycle, ie. When metamorphosis is observed during the pupal stage.

Typical Leafminer     

Cigar Case Bearer (Coleophora caryaefoliella) adult is a brown moth with fringed wing margins up to 9mm across. The tiny lava has a black head and feed beneath the epidermal layer of the leaf and over winters in small cigar-shaped cocoon. Commonly found on Carya species.

Cineraria Leaf Miner (Chromatomia syngenesiae) is in the family Agromyzidae. This insect has a complete metamorphosis: egg, larva, pupa and adult. The adult is a small (2mm) black fly. Female adults puncture the undersides of leaves to feed on the sap. Cream coloured larvae (maggots) are miners, up to 5mm long, and their tunnels appear as a tracery of irregular white lines on the leaves, through which the larvae will be visible on the lower surfaces.  The pupa is darker-coloured, barrel-shaped and up to 2.5 mm in length.

The feeding of females causes small rust-like spots to appear on the upper surface of leaves. The eggs are deposited on the undersides of the leaves. The tunnels of the larvae become wider as the insect grows and may eventually cause the infested foliage to wilt. Heavily infested plants will die; more often, the appearance of the plant is spoilt by the disfigured leaves, even though it will still produce flowers.

Cypress Moth (Recurvaria apicitripunctella) female adult is a small, yellowish with fringed wings and black markings. The larva tunnels into leaves and then ties them together with silken web, it found on Taxodium mucronatum.

Grevillea Leaf Miner (Peraglyphis atimina) a tiny larvae that eats the inner tissue of leaves and forms tunnels that expand as they grow.

The Leaf Miner (Epinotia nanana) is an olive green caterpillar with a brown head that attacks the base of the leaf and webs them together as it progresses. It is found in Tsuga species.

The Leaf Miner (Lithocolletis crataegella) lava forms tunnels in the inner tissue of the leaf, which becomes wider forming blisters that turn light brown. It normally occurs during late spring attacking unfolded leaves of many plant species including Crataegus.

Macadamia Leaf Miner (Arocercops chionosema) larva forms tunnels that lead to blisters in the leaves and the adult moth is brown with silver bands.

Damage Caused

There is a range of symptoms as a result of attack. Damage appears initially as tunnels on the underside of the leaves, which become broader. The leaf may form blisters and turn a rusty colour with patches visible on both sides. Continual feeding can cause the leaf to fall prematurely and give the plant an unattractive appearance. This attack is a serious problem in a forestry situation but is normally insignificant in a domestic garden. Attacks may be sporadic.

                  Banksia integrifolia

Cineraria Leaf Miner

Tunnels begin to appear in early spring and continue through early summer, particularly during cooler, humid periods. The adult fly is inconspicuous and tends to go unnoticed - its presence is indicated by the appearance of the rust-like spots on the leaves as described above. Tunnels of larvae, in which the maggot pupates, may become up to 2mm wide and cover most of the surface of the foliage.

Period of Activity

The larvae are active from summer to autumn and are found from the tropics to temperate regions and generally the eggs are laid on the underside of leaves.

Susceptible Plants

There is a wide range of ornamentals and native plants that are attacked by leaf miners, including vegetables, perennials, annuals, shrubs and trees such as Nyssa sylvatica.

Aquilegia species leaves are attacked by the leaf miner (Phytomyza minuscula) which causes obvious winding white tunnels across the leaf surface.

Betula species are attacked by the leaf miner (Fenusa pusilla). The small black sawfly emerges from the soil primarily during spring. The small worm-like white lava feeds on the fresh new growth, and may cause substantial damage. Adults that emerge later in the season cause less destruction as the lava ignore mature leaves feeding only on new growth.

Buxus species are attacked by the leaf miner (Monarthropalpus buxi) that causes water soaked areas on the underside of leaves as the lava tunnels beneath the epidermal layer.

Cornus species are susceptible to the leaf miner (Chalepus dorsalis) yellowish lava up to 7mm long that tunnels the leaves causing blisters and the adult beetles skeletonise the underside of the leaves.

Leucanthemum and Dendranthema species are attacked by the Chrysanthemum Leaf Miner (Phytomyza atricornis).

Macadamia species and Stenocarpus salignus are attacked by the Macadamia Leaf Miner.

Pericallis x hybridus (Cineraria) is attacked by the Cineraria Leaf Miner (Chromatomia syngenesiae). Leafy vegetables are also susceptible, as are plants in the Asteracea family and related ornamentals such as chrysanthemums, nasturtiums, and gerberas. Sow thistle and other leafy weeds are hosts for this insect. The foliage becomes covered with unsightly, tortuous silvery lines which ultimately ruin the appearance of the plant. Heavy infestations cause wilting and death of the plants. Do not take cuttings from affected plants.

Verbena species are attacked by the leaf miner (Agromyza artemisiae), which mines the leaf margins.

Cultural Control

It is difficult to control leaf miners and damaged leaves may be removed then destroyed from localised infestations.

Biological Control

Many leaf miners are attacked by parasitic wasps and small birds which reduces numbers.

Chemical Control

Chemical treatment includes spraying with dimethoate; note that it is advisable to treat the plants before the larvae pupate and being certain to cover the new growth avoiding reinfestation.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

PEST

   NAME

     Caterpillars (General)

     Various species

Description of the Pest

There are many types of caterpillars from moths or butterflies, cutworms, bag moths, case moths, leaf rollers leaf skeletonises. The larvae generally eat leaves, seeds, flowers or buds by chewing out pieces. The size of the piece will depend on the size of the caterpillar and generally they are voracious eaters. The method of eating varies such as the leaf skeletoniser which leaves a network of veins or whole leaves are consumed.

The larvae have mainly 4 or 5 pairs of prolegs except Loopers which have 2 -3 pairs of prolegs. The number of prolegs can help in identifying the insect.

Small and Large Types     

Casuarina Moth (Pernattia exposita) is gregarious, brown with a large head and tufts of hairs that line the slender body. It grows to 25 mm long and forms a tightly woven cocoon on the side of branchlets. The large female adult moth has a stocky body and generally slow moving, the male is smaller.

The larvae cause extensive damage to A. littoralis, A. stricta, C. cunninghamiana, C. glauca, and C. equisetifolia.

The hairy larva feed on the 'leaves" phyllodes, and stems, this can lead to ringbarking and death of branches.

Monitoring

Place sheets on the ground and disturb (shake) the tree for the larva drop to the ground on silken threads.

Spruce Budworm (Choristoneura fumiferana) is a reddish brown with a yellow stripe on its side and chews on the opening buds and the needles of the host. The adult moth is dull grey with brown bands and spots on the wings, appearing in early summer.  The larva is very destructive in northern hemisphere coniferous forests.

Banksia Moth (Danima banksiae) is a caterpillar up to 60 mm long and is brown with black and white markings on its sides and when disturbed it arch backwards and reveal an extruded red underside, close to its head. The grey adult moth has an orange coloured body with a wing span that is up to 80mm across with black and white markings.

Banana moth (Opogona sacchari) is in the order Lepidoptera. This nocturnal moth as a wing span up to 25 mm wide and is bright yellowish brown with a dark brown spot on the wings.  It has a life cycle that lasts approximately 3 months with the eggs hatching in 12 days and the whitish larva with a reddish brown head is up to, 26 mm long, and lives for 50 days at 15° C. In warmer climates life cycle is quicker with up to eight generations per season. The female moth uses a ovipositor to lay up to 500 eggs in groups of five amongst the crevices of the plant. The voracious larvae tunnel into the plant, avoiding light.  In bananas it infests developing fruit and in ornamental plants it prefers the fleshy stems, particularly in cacti, begonias, African violets and is also a serious pest of Pritchardia and Chamaedorea species. Symptoms include tunnelling activity, which may be difficult to see then dead areas appear on the stems. As the caterpillars destroyed xylem tubes leaves begin to wilt and the plant may collapse and die. In European countries it is a glasshouse pest that is controlled chemically.

Pritchardi species      Banana moth larvae

European Pine Shoot Moth (Rhyacionia buoliana) lays eggs on Pinus species during late spring on the new buds and the emerging caterpillars in late summer feed on the shoots causing them to fold and become deformed, eventually dieing.  A major problem in the pine forests of the northern hemisphere

Large Grass Yellow Butterfly (Eurema hecabe) is a small attractive yellow butterfly. with a wing span of 40 mm that lays its eggs on the feathery leaves on Acacia species such as A. baileyana, (Cootamundra wattle), A. spectabilis (glory wattle). Other plant foods include Cassia spp, Caesalpinia spp, Senna spp. Albizia julibrissin (silk tree) A. paraserianthes (Albizia) sp Aeschynomene sp (Budda pea), Indigofera australis (Australian indigo's), Sesbania cannabina (yellow pea-bush), Senna surattensis (Glossy shower), Leucaena leucocephala (wild tamarind).

The small lava are up to 15mm long, green with white lateral bands and feed on the leaves at night in small groups, hiding under the leaves during the day. Large infestations may strip trees and require control. The larva of this insect does not feed on grasses. The adults are important pollinators of many Australian native plants. Various sub species of this insect are found through out Asia.

Gypsy Moth (Porthetria dispar) lava is a hairy grey caterpillar that is marked with blue and red dots along its back and can grow to 75mm long. It is capable of defoliating large trees and is a major problem for several species. A major problem in the northern hemisphere.

Lawn Armyworm

Lawn Armyworm (Spodoptera mauritia) is a plump, smooth caterpillar that is darkish brown to black with multiple stripes and pattens along its body. It can grow to 50mm long and tapers from the head. They are gregarious and move around in groups, like an army. If disturbed the larva drop to the ground and curl up, "faking death"  The larva pupate in the soil. They are a pest of grasses and monocotyledon crops mainly.

This insect is also found throughout Asia.

Monitoring

Drench a known area with old fashion soap 2L / 1000 cm 2. Note the numbers of larvae emerging.

Oblique-banded Leaf Roller (Choristoneura roseceana) lava feeds on the leaves and forms a nest by drawing the leaf margins together using silk threads. The adult moth is up to 25mm across the wingspan and is reddish brown with three darker brown bands across the wings. This is a problem in the apple growing areas of North America. It feeds on Maples, hawthorns, crab apples, Blackberry (bramble) and raspberries.

Red Humped Caterpillar (Schizura concinna) is a lava has a red head and humps with yellow and black strips on the body. It grows from eggs that were laid on the underside of leaves by the adult greyish brown moth that has a wing span up to 30mm across.

Tailed Emperor Caterpillar (Polyura pyrrhus spp. sempronius) adult is a large butterfly with a wing span up to 110 mm with four long tapering tails and the rear of the wings. The fleshy caterpillar with four obvious backward facing horns on a shield shape head. It is dark green with yellowish bands and transversal stripes over its back and grows up to 80 mm in length.

It is commonly found solitary or in small groups. Found over much on mainland Australia. The adults are attracted to overripe fruits they become drunk on this and so are easy to capture. The larvae feed on many plants including, Acacia baileyana (Cootamundra Wattle, A. spectabilis (Glory wattle), Delonix regia (Poinciana), Cinnamomum camphora (Camphor laurel) Robinia pseudoacacia (Black or false locust) Lagerstroemia indica (Crepe Myrtle), Argyrodendron actinophyllum (Black booyong), Celtis spp (Hackberry), Brachychiton spp (Kurrajongs) Gleditsia triacanthos (Honey locust).

Verbena Moth (Crambodes talidiformis) lays its eggs on the outside of the plant and the small green caterpillar that attacks seed pods by entering and eating the contents. It half emerges while pupating appearing as a small brown bump circled by a black ring. Native to North America

White Tussock Moth (Hemerocampa leucostigma) produces lava that is up to 50mm long. It has a red head with a yellow body that is marked in black and has four tufts of hair. The caterpillars pupate on the branches and the eggs laid by the adult moth overwinter on the trunk and are covered in a white waxy material. They are found on Aesculus species. A pest in North America of Oaks.

Life Cycle

This insect has a Holometabolous life cycle, i.e. it has a larval and a pupal stage.

Distribution of the Pest

Many species are found throughout the world from tropical to temperate regions and most of the adults are capable of by flying

Many hairy caterpillars can be irritating      Leaf Skeletonised

Period of Activity

Most active during the warmer months from spring to autumn.

.

Damage Caused

Leaf Rollers

Caterpillar Inside a Tomato

Susceptible Plants

A wide range of native and exotic plants are attacked and can be a major problem in commercial crops or turf grasses. Plants with soft-textured foliage (eg vegetables, some indoor plants) are preferred, but trees and shrubs are commonly attacked.

Malvaceae Abutilon spp, Hibiscus spp and other members of the family are attacked by the castor oil looper, Croton caterpillar (Achaea janata) which feed on leaves. The tip borer Cotton tipworm (Crocidosema plebejana), Rough bollworm (Earias huegeliana) which feeds on young stems, flowers and seeds. A leaf miner (Phyllonorycter spp)

Acer saccharinum and Fagus species are attacked in North America by the Maple Leafcutter (Paraclemensia acerifoliella) that forms a small cocoon in leaves that it skeletonises.

In Australia Case moths and Painted apple moths (Teia anartoides)

Ailanthus altissima is attacked by the Cynthia Moth (Samia cynthia) light green lava, which eats leaves and the Ailanthus Webworm (Atteva aurea) which are olive-brown caterpillars that form web nests in the leaves.

Antirrhinum species are attacked by the Leaf Tier (Udea rubigalis) lava. This caterpillar eats pieces out of leaves and binds them together forming a nest. It is more commonly found in glasshouse culture.

Berberis species may become infested with the Barberry Worm (Omphalocera dentosa). This small caterpillar is black with white spots, up to 14mm long and feeds on young shoots and leaves. It also binds the shoots with a silken thread to form a nest.

Betula species are attacked by the Leaf Skeletonizer (Bucculatrix canadensiella). The small adult moth has brown wings with a whitish underside and its yellow green, 7mm long lava skeletonise the undersides of the leaf turning it brown.

Brachychiton, Senna and feathery-leaved Acacia species are attacked by the Tailed Emperor Caterpillar, particularly in dryer periods.

Catalpa species are attacked Catalpa Sphinx (Ceratomia catalpae). This large yellow and black Caterpillar grows to 76mm long and attacks the leaves.  Large infestations can completely stripped a tree and control is carried out by spraying.

Calendula and Canna species are attacked by the Woollybear Caterpillar (Diacrisia virginica) which has yellow and black lines down its body is up to 50mm long and eats the leaves or flower buds. In Canna species the chewed holes tend to be in a straight line across the leaf.

Celtis species are attacked by the Spiny Caterpillar (Nymphalis antiopa) which is reddish, up to 50mm long and feeds on the leaves at the top of branched in groups.

Cheiranthus species are attacked by the Diamond-backed Moth (Plutella maculipennis) lava, which is a small green caterpillar to 14mm long that feeds on the underside of leaves and may form a shot hole appearance. It forms a small cocoon to pupate in and in cooler climates it may be found in glasshouses.

Cotinus, Fraxinus, Betula, Cornus, Crataegus, Aesculus, Tilia, Acer, Quercus and Populus species are susceptible to attacked by the Oblique-banded Leaf Roller (Archips rosaceana)

Iris and Antirrhinum species are attacked by Verbena Moth.

Picea, Abies, Tsuga and Pinus species are attacked by Budworm commonly found in the northern hemisphere.

Populus and Carya species are attacked by the Red Humped Caterpillar which chews the leaves.

Quercus species are attacked by several caterpillars including Saddleback Caterpillar (Sibine stimulea) and Datana Caterpillar (Datana ministra) that feed on the leaves.

Samanea saman is attacked by several caterpillars (Ascalapha odorata, Polydesma indomita and Melipotis indomita). These caterpillars defoliate the tree but cause no long term problems.

Spiraea, Fraxinus, Betula, Cornus, Crateagus, Acer, Quercus and Populus species are attacked by the Oblique-banded Leaf Roller.

Ulmus, Salix, Crateagus, Tilia, Quercus and Populus species, Pseudotsuga menziesii are attacked by the Gypsy Moth (Porthetria dispar).

Ulmus species are attacked by the Spring Cankerworm (Paleacrita vernata), which chews the leaves during spring and the Fall Cankerworm (Alosphila pometaria), which also eats the leaves during autumn. Ulmus  species are also attacked by several caterpillars including the lava of the Leopard Moth (Zeuzera pyrina) and the Tussock Moth (Hemerocampa leucostigma).

Cultural Control

Small numbers may be removed by hand and squashed while others species such as the Casuarina Caterpillar drop to the ground when disturbed by hitting with a stick or shaking the plant. On the ground they can be squashed or collected and placed in a bucket of soapy water.  All rubbish around plants and glasshouses should be cleared as certain moths overwinter in such places.

Biological Control

There are many natural predators that reduce numbers including birds, lizards, frogs; other predators are wasps, viruses, and fungi.

Chemical Control

The small plant may be sprayed using Pyrethrum-based insecticide to reduce numbers or dusted with an equally environmental friendly chemical. In severe cases crops may be sprayed with Carbaryl.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

Note: Plants affected by this pest are Deer Resistant plants not the susceptible plants.

 

PEST

   NAME

     Deer

     Cervus species

   ORDER

     Artiodactyla

   FAMILY

     Cervidae

 

 

Description of the Pest

There are two species of the deer in North America, the Whitetail (Odocoileus virginianus) and the Mule deer (Odocoileus hemionus) with several regional variations such as the Pacific coastal Blacktail (O.h. columbianus) which is regarded as a sub-species of the Mule deer.

 

The Whitetail on average grows to 112 cm (44in) tall and 180 mm (70 in) long and weigh 68 kgs (150lbs). The fir colour varies according to its environment but generally it is reddish-brown during summer and grey-brown in winter with a pure white underside on its tail. When the tail is erect it is known as the "white flag". Its antlers consist of two main beams from which the points emerge.

 

The Mule deer grow to 105 cm (42 in) tall and are up to 200 cm (80 in) long with the adult buck weighing up to 137 kgs (300 lbs) and the does up to 80 kgs (175 lbs). The fir is generally tawny brown during summer and during winter it has a heaver grey-brown to blue-grey coat with a small white tail that is tipped in black. The other distinguishing features are its ears that are up to 300 mm (1 ft) long (mule-like) and its antlers, with the two beams that are forked into smaller beams, which inturn fork again and again.

 

The Blacktail deer (Pacific coastal Blacktail) grows to 97 cm (38 in) tall and is up to 105 cm (60 in) long and weighs on average 73 kgs (160 lbs). The fir is generally tawny brown during summer and during winter it has a heaver grey-brown to blue-grey coat with a tail that is dark brown at the base then changing to black for 50% of its length. The antlers consist of two beams that are forked into smaller beams, which inturn fork again and again.

 

Appearance and Distribution of the Pest

The Whitetail deer are found throughout eastern United States, on the coast and inland but are not commonly seen in California, Utah or Nevada. They do not migrate but congregate together (yard up) during winter and feed in a part of their existing territory.

 

The Mule Deer are found in the western part of North America from South eastern Alaska to Mexico and from the Pacific coast to Texas. They migrate from highland mountain meadows to southern or lower snow free forested valleys during winter.

 

The Blacktail deer are found on the Pacific coast from Alaska to northern California. There is both resident and migratory Blacktails. The  migratory Blacktails move southwards during late autumn at the first sigh of snow or heavy sustained rain and the resident Blacktails seek cover their existing territory amongst woodlands during the winter months.  

 

Life Cycle

All Deer breed from autumn to early winter and the does give birth from late spring to early summer.

 

Period of Activity

Deer are most active from spring to autumn but can be troublesome during winter when the feed is scarce. In some regions urban landscapes become the major food source both in summer and winter.

 

Damage Caused

Browsing deer will feed on almost any plant and is most commonly noticeable during spring feeding on the new growth or twigs and stems leaving a shredded appearance. Deer also rub their antlers against trees damaging bark and snapping off small branches, this action also incurs damage under hoof as plants, lawns and garden structures are trampled on.

 

Susceptible Plants

Some plants are more palatable to deer but when a deer is hungry or during drought conditions there are no "Deer Proof" plants. There is a range of plants that have a bad taste and are not destroyed and are regarded as (deer resistant plants). Deer resistant plants are the plants that are attached to this file not the susceptible plants.

 

Cultural Control

There are many cultural controls that have been tried to move browsing deer such as frightening them with strobe lights, pyrotechnics or tethered savage dogs. These actions are only temporary and may cause more trouble as the stampeding animals move off. Fencing and netting can be an effective method of discouraging hungry deer from gardens but may be expensive on a large scale and require maintenance. There are several types of fences which include conventional 2.2m (8 ft) deer-proof woven wire fences or single-wire electric fences and slanted deer fences. Plant selection can also be effective, by using less desirable plants (deer resistant plants) as an outer border to the more desirable plant species and  thus discouraging the deer to enter the garden. Hedges and windrows of less desirable thorny plants can also be a deterrent to browsing deer.

 

Chemical Control

There are two main types of repellents contact and area. Contact repellents are applied directly to the plants and deter deer with a bad taste or smell. They can be applied by rubbing or spraying on to the plants and commonly used in an egg mixture. The commercial products have proven to work better than home remedies which include soap or chilli mixtures and hanging bags of human hair.

Area repellents rely on an offensive odour and are placed around areas that are frequently visited.

 

Contact your local distributor for available types and application.

DISEASE

 

   NAME

     Rust (General)

     Various Rust Species

 

Description

Generally this fungal problem involves many species causing a range of symptoms, but generally produces pustules that release reddish - brown spores. Most fungus is specific to its host and normally will not infect other plant species.

 

Pustules

 

Symptoms

The upper leaf surface develops red, brown or yellow areas and the underside produces bright yellow to orange spores that correspond to the patches above.  Infested leaves become brown in patches, fall prematurely and flower and fruit may also be infected.  This overall, results in a loss of vigour and in small plants may lead to death.  

 

Pelargonium x hortorum

 

Myrtle Rust (Puccinia psidii) This fungal disease infects plants in the Myrtaceae family and was only recently detected in 2010 and has since spread across eastern Australia from the Northern Territory to Queensland, NSW, Victoria and Tasmania. This rust attacks soft and actively growing foliage or shoots with varying symptoms. It normally starts as small purple spots on the leaves from which spores form in yellow pustules that fade to grey as the infection matures and can merge creating leaf distortion and death of the plant. 

The life cycle starts when the powdery yellow spores are distributed by wind to other plants where they germinate and start to grow by piercing the plant cells to obtain nutrients. Germination occurs in dark moist positions with a temperature between 15° to 25°C and the new pustules can release spores in 10 to 12 days, (spores remain viable for 3-months). The spores spread rapidly by wind, water, insects or animals. They are also distributed by plant material, clothing, shoes and vehicles.

 

 Puccinia psidii

 

 

Needle Rust (Melampsora farlowii) infects the new leaves turning them to yellow and fall from the shoot giving the branch a scorched appearance. The fruiting bodies are found on the underside of the leaf and is waxy-red.

 

 

Rust in Poplar (Melampsora species). A fungal problem involving at least two species (Melampsora medusae) and (Melampsora larici-idaei).

The upper leaf surface becomes flecked with yellow to light green and the underside produces bright yellow orange spores that correspond to the patches above.  Infested leaves become brown in patches, fall prematurely and shoots may die back as a result of not being hardened off to the elements.  This overall, results in a loss of vigour and in small plants may lead to death.  

The source of the fungus is from other infected plants or fallen leaves and is dispersed by wind.

Host plants include Lombardy Poplars particularly Populus nigra 'Italica' and cottonwoods.

 

 

White Rust (Albugo candida) forms snow white pustules that contain colourless spores that turn yellow then brown and are found on the underside of leaves.

 

White Pine Blister Rust (WPBR) is caused by the fungus (Cronartium ribicola). It is a obligate parasite requiring a living host to survive. The life cycle requires two host species with part of it life on the Pinus species and the other part on Ribes species. First cankers or sores appear on the Pinus species realising spores that land on the Ribes species infecting it. The infection produces a different type of spore that land on the needles and growing branches of the Pinus species and eventually forming cankers. The spores are spread by wind and prefer cool moist conditions. Symptoms include brown spots on the needles and the appearance of dead branches in the crown. Cankers will also appear on the trunk and it tends to attack young trees. Control methods include removal of Ribus species in the affected areas and breading naturally resistant Pinus species.

 

The Rust (Endophyllum sempervivi) affects Sempervivum species by infecting the young leaves and eventually the crown. The mycelium then travels to the roots and extends into any off shots. Leaves that are infected turn yellowish, grow longer and are thin. Persistent infection may kill the plant.

 

Source and Dispersal

The source of the fungus is from other infected plants or fallen leaves that contain the fruiting bodies and is dispersed by wind.

 

Favoured Conditions

Generally rust is more prevalent during summer, preferring warm humid conditions and particularly when the leaves are damp.

 

Affected Plants

A wide range of ornamental annuals, perennials, ferns, trees, shrubs including, Hibiscus species that are infected by Kuehneola malvicola predominantly in southern USA.

 

Abies species are infected by many types of rust including (Milesia fructuosa) and (Uredinopsis mirabilis).

 

Abutilon, Phymosia and Alcea species are infected by the rust (Puccinia heterospora).

 

Alnus species are occasionally infected with Leaf Rust (Melampsoridium hiratsukanum) which forms yellowish pustules on the leaves that develop turning the leaf brown.

 

Amelanchler species and Calocedrus decurrens are infected by several rust species including (Gymnosporangium libocedri).

 

Antirrhinum majus (Snapdragon) is infected by the rust (Puccinia antirrhini). This fungal problem that infects the epidermal layer on the leaf underside, forming pale green areas that are raised and split open revealing reddish brown spores that have a dusty appearance.  

As the infestation grows, concentric rings of spore pustules appear around the original infection.  The corresponding position on the upper leafs surface turns yellow eventually causing the leaf to wilt and die.  The infestation is not restricted to the leaves; all above ground parts of the plant are susceptible and infected plants transmit the fungus dispersing it by wind.

Infected plants should be removed and destroyed.

 

Anemone and Prunus species are infected by the rust (Tranzschelia pruni-spinosae) that stimulates abnormal growth in the plant during spring.

 

Aquilegia, Anemone, Delphinium and Clematis species are infected by the Rust (Puccinia rubigo-vera var. agropyri).

 

Arctostaphylos manzanita is infected by the rust (Pucciniastrum sparsum) occurring in coastal regions but is not normally detrimental to the plant.

 

Artemisia species are infected by the rust (Uromyces ari-triphylli) which is a systemic disease that is transmitted through seeds. It causes the leaves to turn yellow then die and can infect all parts of the plant except the roots.

 

Bambusa species are infected by the rust (Dasturella divina) which forms elongated brownish strips on the leaves.

 

Berberis species may be infected by the Rust (Puccinia graminis) that forms orange spotting on the leaves. It certain regions plants infected with this rust must be removed and destroyed to avoid infecting neighbouring agriculture crops.

 

Betula species may be infected by Leaf Rust (Melampsoridium betulinum) that forms reddish-yellow spots on the leaves and heavy infestation can defoliate the tree. The host tree changes to Pseudolarix species during the sexual stage and causes blistering of the leaves.

 

Calendula species may be infected by the Rust (Puccinia flaveriae).

 

Callistephus and Solidago species may be infected by the Rust (Coleosporium solidaginis) which forms bright yellow spots particularly on new foliage or young plants.

 

Canna species may be infected by the rust (Puccinia Thaliae).

 

                  Canna indica

 

Centaurea species are infected by the rust (Puccinia cyani) and (Puccinia irrequisita) which can cover the stems and leaves.

 

Cleome species are infected by the rust (Puccinia aristidae) but rarely requires control.

 

Dianthus species are infected by the rust (Uromyces dianthi) which forms powdery brown spots that appear on both sides of the leaves. The leaves curl and die and the plant becomes stunted. This is a common problem that occurs when grown in a protected enclosure (hot house).

 

Ficus species are infected by the rust (Cerotelium fici) which forms small brown spots, and causes the leaves to turn yellow then fall prematurely.

 

Fuchsia species are infected with (Pucciniastrum epilobii). This fungus caused purplish red blotches on the upper leaf surface, that become dry in the middle and result in a brown patch with purple edges.  On the underside of the leaf, corresponding to the patches, yellow orange spores form.  Heavily infected leaves become yellow and drop prematurely.  This leads to a loss of vigour in the plant and infected plants transmit the fungus.  

Certain cultivars are more susceptible than others, particularly 'Orange Drops' and 'Novella'.

 

Hydrangea species is infected by (Pucciniastrum hydrangeae) causing yellowish brown pustules to appear on both sides of the leaf. The leaf becomes dry and brittle.  

 

                  Iris species

 

Iris  and Dietes species are very susceptible to the rust (Puccinia iridis). Leaves form rusty red powdery spots that enlarge. They are appear on both sides of the leaves causing the surrounding area to turn pale yellow then brown and the black spores appear soon after, overwintering on dead infected leaves. Plants may be heavily infected but normally survive attack.

 

Larix species are infected by several Needle Rusts including (Melampsora paradoxa), (Melampsora medusae) and (Melampsoridium betulinum). The fungi attacks the needles predominantly towards the branch tips turning them yellow and eventually killing them . The underside of the leaf develops pale yellow fruiting bodies.

 

Lupinus species are infected by three species of rust including (Puccinia andropogonis var onobrychidis).

 

Malus andChaenomeles species may be infected by the rust (Gymnosporangium juniperi-virginianae) or (Gymnosporangium clavipes) which forms brown or bright orange spots on the leaves or twigs and can defoliate the tree. Juniperus virginiana and Mespilus germanica may also be infected by rust.

 

Mathiola and Arabis species are infected by White Rust.

 

Pinus species are infects by the Comandra Blister-rust (Cronartium comandre).

 

    

Plumeria rubra                           Leaf upper surface                    Leaf underside

 

Plumeria species are susceptible to the rust (Coleosporium plumeriae). Leaves and flowers may be infected with the underside forming bright yellow pustules and causes premature leaf or flower drop.

 

Populus nigra 'Italica' is infected by the rust (Melampsora species) which forms pustules to form on the leaves turning them brown and causing premature leaf drop.

 

Rhododendron and Tsuga species are infected by the rust (Pucciniastrum vaccinii) and is commonly found in nursery stock, spreading rapidly. Tsuga species are also infected by Needle Rust.

 

Ribes species are infected by the rust (Cronartium ribicola). This leaf rust appears on the underside of the leaves (preferably older leaves) forming dusty brown pustules and is a serious problem. This rust only appears when White Pine (Pinus strobes) grows near where the alternate stage of the fungus occurs.

 

Rudbeckia species are infected by several species of rust including (Puccinia dioicae) and (Uromyces rudbeckiae).

 

Salix species are infected by four types of (Melampsora species).

 

Senecio, Bellis and Calendula species are infected by the rust (Puccinia lagenophora) which forms blister-like pustules that release brown spores.

 

Sorbus aucuparia is affected by several rust from the (Gymnosporangium species) causing circular yellow spots, that appear on the leaves during summer and develop into orange cup-shaped fruiting bodies.

 

Trillium species are infected by the rust (Uromyces halstedii) that damages the leaf surface.

 

Festuca arundinacea      Rust

 

Turf Grass are susceptible to rust (Puccinia species) and (Uromyces species), causing yellow flecks to appear on the stems and leaves. These markings enlarge before the pustules form and in severs cases the lawn has a yellow, red or brown appearance.

The infection appears from spring to summer under humid low light conditions and turf that is under stress or with excessive nitrogen in the soil is more susceptible. Many species may be infected including Lolium perenne (Perennial Ryegrass) and Poa pratensis (Kentucky Bluegrass).

 

                  Rust on Perennial Ryegrass

 

Viburnum species are mildly affected by two types of rust (Coleosporium viburni) and (Puccinia linkii).

 

Viola species are infected by the rust (Puccinia violae) which forms green spots on the underside of the leaves. It is not commonly seen on cultivated plants.

 

Non-chemical Control

Cut off and destroy any infected branches, fallen leaves and remove heavily infected plants. Improve the culture by, pruning to improve air circulation, allow space between plants and avoid over crowding.  Avoid planting susceptible species.  Plants that are infected with a systemic form should be removed and destroyed

 

Chemical Control

Not possible to spray large trees but young plants may be treated with a protectant fungicide such as wettable sulphur. In a domestic garden small plants such as Fuchsia species may be sprayed with a protectant chemicals as symptoms appear, aided by the removal of existing infected leaves.  Under commercial conditions stock may be sprayed with a fungicide such as oxycarboxin.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

DISEASE

   NAME

     Powdery Mildew

     Various Powdery Mildew Species

Description

Powdery mildew covers arrange of fungal infections most with simular characteristics of white powdery areas appearing on the leaves and flowers.

     White powdery area     

Symptoms

Powdery mildew (Oidium species) affects the following five plant groups with slightly different characteristics.

Cucurbits firstly form white spots on the underside of the leaves. Under optimum conditions the fungus spreads to the upper surface covering the entire leaf causing it to die. It may also extend to the stems slowing the growth of the plant and may reduce the size of the fruit.

Grape leaves, flowers and fruit are attacked with the appearance of greyish-white powdery spots. Infected flowers set poor quality fruit and infected fruit splits open and dries out.

Pawpaw leaves become infected on the underside at first then spreading covering the entire leaf. The fruit forms irregular light grey spotted areas that damages the surface and under the surface causing the fruit to misshapen and reducing its market value.

Rose leaf and buds are covered in a fine white powdery coating and in severe cases it extends to the stems. When young leaves are infected they become distorted and older leaves develop blackened areas. Infected flower buds may fail to open and opened blooms may be discoloured or distorted.

Strawberries show different signs of infection with the leaf margins first rolling upwards then developing purplish irregular blotches along the veins.  The infected flowers may fail to set fruit and if fruit is produced it is small, hard fails to ripen. Semi mature fruit that is infected has dull appearance and may form cracks or split open.

The Powdery Mildew (Sphaerotheca lanestris) infects leaves and twigs. The under side if the leaf firstly has a white mealy growth that matures to felt-like brown mycelium that can cover the entire leaf, and the twig tips. It is only one of the many types that infect Quercus species.

Source and Dispersal

The spores overwinter in fallen leaves, dormant buds, seed and infested plants. It is dispersed by wind.

Favoured Conditions

Generally it prefers warm humid conditions, but failing to germinate when it is raining. The fungus that attacks Pawpaw prefers cooler conditions disappearing in the warmer months.        

Affected Plants

There are many plant species ornamental trees and shrubs that are attacked by Oidium species including; Roses, African Violets, Cucurbits, Grapes, Pawpaw, Strawberries, Hydrangeas, Ajugas, Antirrhinum, Oaks and Photinias.

Acer species are infected by the powdery mildews (Uncinula circinata) and (Phyllactinia corylea) but are not normally serious.

Aesculus species are infected by the powdery mildew (Uncinula flexuosa) which forms a white mold on the underside of the leaves.

Arenaria,Cuphea, Erica and Eschscholtzia species are infected by the powdery mildew (Erysiphe polygoni). This fungus is greyish or white and covers leaves or young shoots. Heavenly infected leaves turn brown and fall from the plant. The plant eventually dies.

Aster species are infected with the powdery mildew (Erysiphe cichoracearum) which is more prevalent on the lower part of the plant.

Ceanothus, Corylus, Platanus, Syringa and Weigela species are infected by the powdery mildew (Microsphaera alni) particularly London Plane. The mycelium forms a felt-like cover on the leaves.

Celtis species are susceptible to the powdery mildew (Uncinula parvula) and (Uncinula polychaete). This fungal problem can affect either side of the leaf, which can have spots or be completely coved in mildew. The fruiting bodies appear on the opposite side of the mildew.

Cornus species leaves are infected by the powdery mildew (Microsphaera alni) and (Phyllactinia corylea), covering the leaves in a whitish fungus.

Dahlia species are infected by the powdery mildew (Erysiphe cichoracearum) that forms white powdery areas on the leaf surface.

Lagerstroemia species are infected by the powdery mildew (Uncinula Australiana) that forms white powdery growth on the leaves and may also distort the infected foliage.

Populus and Salix species are infected by a white powdery mildew (Uncinula salicis) that produces black fruiting bodies with a curled tip, but is not normally a major problem.

                  Quercus robur

Quercus species are susceptible to several powdery mildew fungi including (Sphaerotheca lanestris), (Erysiph trina) and (Phyllactinia corylea). Generally white mealy growth appears on the leaves, normally on the underside turning the infected areas brown and then the leaf dies. The infection may spread to the twig tips causing dieback. Control may be difficult and unwarranted on large trees but nursery stock may be sprayed with a fungicide during susceptible periods.  

Rosa species are also infected by the powdery mildew (Sphaerotheca pannosa).

Rudbeckia and Senecio species are covered in white fungus (Erysiphe cichoracearum) which infects leaves, flowers and stems. This results in the plant becoming stunted.

Senecio species are infected by the powdery mildew (Sphaerotheca fuliginea) which forms circular white powdery areas on the leaves.

Spiraea species are infected by the Powdery Mildew (Microsphaera alni) and (Podosphaera oxyacanthae).

Ulmus and Rhododendron (Azalea) species are also infected by (Microsphaera alni). Circular patches of white powdery growth appear on the leaves.

Veronica species are sometimes infected by the powdery mildew (Sphaerotheca humili) causing a white coating to appear on the leaves. Not normally a major problem.

                 

Zinnia elegans are commonly infected by the powdery mildew (Erysiphe cichororacearum), which appears on both sides of the leaves as a greyish powdery cover and may be transmitted by seed.

Non-chemical Control

Choose less susceptible species and when planting space the plants to allow good air circulation. Avoid overwatering and try to keep the foliage dry. Affected plants may be dusted with powdered sulphur or sprayed with a milk mixture to discourage mildew. Vegetables that are infected with mildew should be removed and replaced with new young plants, as they are more resistant to infection.

Chemical Control

Prenatitive spraying during warm humid conditions using a suitable fungicide such as wettable sulphur, bitertanol, carbendazim, fenarimol and triforine helps control the problem.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

DISEASE

   NAME

     Leaf Spot (General)

     Various Leaf Spot Species

Description

There is a wide variety of fungal leaf spots that infect perennials, shrub and trees. Some are specific to the host while others can affect a range of plants.

Symptoms

Generally light brown to purplish or blackish spots appear on the leaf and form concentric rings of fruiting bodies. The spots may leave holes, perforating the leaf or expand with pale green to yellowish margins and when the holes merge the leaf normally dies. There are many different types of leaf spot, some are discussed below.

Alocasia species     

Alternaria Leaf Spot (Alternaria nelumbii) forms a small reddish brown spots that are boarded in light green, and as they develop in size the leaf curls and dies from the margin inwards. Normally occurs on Nelumbo species (water lilies).

Helminthosporium Disease

Helminthosporium Disease (Bipolris species), (Drechslera species) and (Exserophilum species) are responsible for several leaf spots that occur on all Turf Grass species. Generally they form black or white spots that may be faded and produce masses of spores in the thatch during late summer, under humid conditions. The life cycle is short and when conditions are favourable spores are splashed onto the foliage from the thatch, causing wide spread infection. Cynodon dactylon (common couch) is most susceptible and found in bowling or golf greens where it is a serious problem.

Banana Leaf Spot     

Banana Leaf Spot (Mycosphaerella musicola) is found on many species of banana causing pale yellow streaks on the young leaves to turn brown with dark spots. The leaf then becomes dried, brown and dead commencing from the margins, eventually the leaf dies. Control requires removal of infected foliage or the spraying of a fungicide and fungicides should not be used during the fruiting period.

                  Lophostemon confertus (Brush Box)

Leaf Spot on Brush Box (Elsinoe species). This is a casual fungus that attacks the epidermal layer of the leaf, forming circular spots that are up to 25mm across and are often restricted by the main vein.  These spots are a dull yellowish brown but can also have purplish patterns.  A leaf may have more than one spot develop on its surface and normally appears on scattered leaves throughout the tree.  This doesn't affect the vigour of Lophostemon confertus.

Palm Leaf-scab (Graphiola phoeicis) appears as yellow spots and develop into scabs or warts that are outwards hard and dark but with a soft centre with powdery yellowish brown spores. The infected leaves eventually die.

Palm Leaf Spot, Chamaedorea elegans

Palm Leaf Spot (Pestaloptiopsis species) appears as a small spot with a dark centre on the leaves and affects palms that are growing in shaded humid positions and normally control is not required, though infected fronds should be removed.

Source and Dispersal

Infection source is other contaminated plants and the spores are spread by wind or by splashing water.  The fruiting bodies are black spots that appear on the damaged tissue releasing spores.

Favoured Conditions

This fungus prefers a warm humid environment and leafy plants with soft new growth, particularly if they are crowded.

        

Affected Plants

There are many ornamental and native plants that are hosts to a wide range of fungal leaf spots. Some specific ones are listed below. Plants such as Cornus or Paeonia species are infected by a large variety of leaf spots, while other plants attract a specific leaf spot.

Generally a healthy plant can tolerate fungal leaf spot attack, though it may make the plant look unsightly. In trees and shrubs it is difficult to control and generally not necessary, but in perennials and annuals control may be necessary in order to save the plant.

Acalypha and Arctotis species are infected by up to three leaf spots including (Cercospora acalyphae) and (Ramularia acalyphae) that rarely require control.

Acer species are infected by Purple Eye (Phyllosticta minima) which forms spots with brownish centres and purplish margins causing the death of the leaves.

Acer species are also infected by Tar Spot (Rhytisma acerinum) which forms round black spots that have yellow margins. Not normally seen on cultivated trees, but seen in forests.

Adiantum, Asplenium, Blechnum, Cyathea, Davallia, Nephrolepis, Platycerium, Polypodium and Pteris species are infected by the leaf spot (Pseudocercopora species) which forms circular brown spots on the fronds and heavy infection can defoliate a plant.

Aesculus species are occasionally infected with the leaf spot (Septoria hippocastani) which forms small brown spots.

Agave species are susceptible to the leaf spot (Coniothyrium concentricum), which appear as greyish spots up to 20mm (1in) across with concentric rings and black fruiting bodies. Affected leaves are destroyed as the infection spreads.

Albizia julibrissin is susceptible to the fungal leaf spot (gloeosporium aletridis), which does not normally require control.

Amelanchler, Chaenomeles, Crataegus and Rhaphiolepis species Mespilus germanica are infected by the leaf spot (Fabraea maculata) which may cause considerable damage during wet periods.

Aquilegia species can be infected by three types of Leaf Spot including (Ascochyta aquilegiae), (Cercospora aquilegiae) and (Septoria aquilegiae), normally appearing during humid conditions forming spots on the leaves.

Arbutus species are infected by two leaf spots (Septoria Unedonis) which produces small brown spots on the leaves and (Elsinoe mattirolianum).

Arctostaphylos manzanita is infected by the leave spot (Cryptostictis arbuti) which damages leaves but is not normally detrimental to the shrub.

Aspidistra species are infected by the leaf spot (Colletotrichum omnivorum) causing whitish spots on the leaves and petiole.

Aster species are infected by many leaf spots including (Alternaria species), (Cercosporella cana), ( Ovularia asteris) and (Septoria asteris).

Aucuba species are infected by several leaf spots, usually as a secondary infection after aphid attack. These include (Phyllosticta aucubae) and (Phyllostica aucubae).

                     Azalea

Azalea (Rhododendron species) are susceptible to Leaf Scorch (Septoria azalea). This fungal disease forms reddish- brown spots which expand and engulf the leaf, with fruiting bodies appearing in the centre. Infected leaves die, then fall and the branchlets wilt. This problem is more serious during wet periods and may require control using a fungicide.

Banksia robur

Banksia species are infected by several leaf spots causing chlorotic areas that have brown centres and is not normally a major problem for the plant.

Betula species may be infected by the Leaf Spots (Gloeosporium betularum) that forms brown spots with darker margins and (Cylindrosporium betulae) that also forms brown spots with faded indefinite margins.

Bougainvillea species are infected by the leaf spot (Cercosporidium bougainvilleae) which forms rounded spots with dark margins that yellowish ting. Infected leaves die and fall from the plant.

Calendula species are infected by the Leaf Spot (Cercospora calendulae) which rapidly infects the plant spotting the leaves and killing the plant.

Callicarpa species may be infected by the leaf spot (Atractilina callicarpae) forming irregular brownish spot or (Cercospora callicarpae) which can defoliate the plant in subtropical climates.

Campsis species may be infected by several fungal leaf spots including (Phyllosticta tecomae), (Septoria tecomae) and (Cercospora duplicata).

Carpinus species are infected by the leaf spots (Gloeosporium robergei), (Gnomoniella fimbriata) and (Septoria carpinea), all are minor infections not normally requiring control.

Carya species are infected by several leaf spots including (Gnomonia caryae) that infects leaves with irregular reddish spots on the upper surface with corresponding brown spore producing spots on the underside. It also has a secondary spore release that occurs on the dead leaves where it over winters. Other leaf spots include (monochaetia desmazierii) and (Marssonina juglandis).

Ceanothus species are susceptible to the leaf spot (Cercospora ceanothi) and (Phyllosticta ceanothi) both are of minor importance not requiring control.

Celtis species are infected by many leaf spots including (Cercosporella celtidis), (Cylindrosporium celtidis), (Phleospora celtidis) and (Septogloeum celtidis).

Chrysanthemums species are infected by the leaf spot (Septoria species) which forms yellow spots appear toward the edge of the leaves; these become enlarged brownish patches with yellow margins.  Damaged areas may converge and in severe attacks and the leaves may fall prematurely or flower production is reduced.

Clematis species are infected by the fungal disease (Ascochyta clematidina) which may cause stem rot or leaf spots that are water soaked areas with reddish margins. The infection spreads from the leaves to the stem causing wilting and eventually girdling the stem killing the plant. There are many fungal leaf spots that infect this plant including (Cercospora rubigo) and (Septoria clematidis)

Dracaena deremensis

Cordyline and Dracaena species may be infected by the leaf spot (Phyllosticta maculicola) which forms small brownish spots that have yellowish margins and has black fruiting bodies that forms coils of spores. These plants are also susceptible to other leaf spots such as (Glomerella cincta) and (Phyllosticta dracaaaenae). Keep foliage dry to avoid infection.

Cynodon dactylon,  Pennisetum clandestinum and many other Turf Grasses are susceptible to Helminthosporium Disease.

Daphne species are infected by the leaf spot (Gloeosporium mezerei) and (Marssonina daphnes) both of which form thickish brown spots that are seen on both sides of the leaves. Infected leaves turn yellowish before dieing.

Dendranthema species are infected by many leaf spots such as (Septoria chrysanthemi) which first forms yellowish spots up to 25mm (1in) across that become black. Infected leaves die prematurely and persist on the plant.

Dianthus species may be infected by the leaf spot (Septoria dianthi). It forms light brown rounded spots that have a purplish border. The scattered spots on the lower leaves can also be found on the stems and the spores are dispersed by water from the tiny black fruiting bodies.

Dieffenbachia species are infected by several leaf spot fungi including (Cephalosporium species) and (Myrothecium species).

Eucalyptus species

Eucalyptus species are infected by many fungal leaf spots such as (Mycosphaeralla species), (Hendersonia species) and (Monocheatia monochaeta). Generally leaf spots appear on the juvenile or new leaves causing brownish spots that enlarge and may have a purplish halo around the margin.  Mature adult leaves are not normally infected and the trees rarely require control measures.

Fern species are infected by the leaf spot, (Alternaria polypodii). This fungus appears as brown circular or oblong spots that congregate along the margins of the pinnae causing the fronds to turn brown and die.  It is spread by wind currents from plant to plant and control methods include removing infected fronds and maintaining a drier atmosphere.

Ficus species are infected by various fungal leaf spot including (Pseudocercospora species). Generally the fungal attack forms circular or irregular dark coloured spots on the leaves eventually causing them to fall prematurely.

Ficus elastica is susceptible to many fungal leaf spots including (Alternaria species), (Leptostromella elastica) and (Phyllosticta roberti).

                    Strawberry

Fragaria x ananassa (Strawberry) is infected by the fungal leaf spot (Mycospharella fragariae). The mature leaf is initially infected with well defined brown spots that that turn light grey with red-purplish margins. As the spots merge they form large brown blotches and the leaf turns yellow then dies. This fungal attack normally occurs on plants in poor health and can be a serious problem early in the season seriously damaging stock.

Fraxinus species

Fraxinus species are infected by the leaf spot (Gloeosporium aridum) giving the leaf a scorched appearance as large blotches appear from the margin or apex and turn brown with a papery texture. It is more prevalent during rainy periods and infected leaves fall prematurely. Collect and depose of fallen leaves otherwise control is not normally required.

Fuchsia species may be infected by the leaf spot (Septoria species) or ( Cercospora species), both form spots with dead centres and dark margins.

Gladiolus species are infected by Hard Rot or Leaf Spot (Septoria gladioli). On the corms reddish brown circular water soaked spots become large and sunken. These areas dry out and form obvious margins. The leaves may also have these symptoms but is not commonly seen.

Hemerocallis species are infected by several leaf spots including (Cercospora hemerocallis) and (Heterosporium iridis). These may be in the form of black spots or brownish spots that converge killing the leaf. Infected leaves should be removed and burnt.

Hibiscus species

Hibiscus rosa-sinensis, Hibiscus syriacus and Hibiscus tiliaceus are susceptible to several fungal leaf spots including (Ascochyta abelmoschi), (Cerospora kellermanii) and (Phyllosticta hibiscina). All cause spotting or blotching of the leaf surface; remove and destroy infected parts.

Hydrangea species are infected by four fungal species including (Ascochyta hydrangeae), (Phyllosticta hydrangeae) and (Septoria hydrangeae).

Iris species are infected by several fungal leaf spots including (Alternaria iridicola) and (Macosphaerella species).

Iris species are also infected by the leaf spot (Didymellina macrospore) that forms greyish spots with brown water soaked borders and coalesce on the upper part of the leaf. This casual organism commonly occurs after flowering killing the leaves but will not infect the bulbs. The bulbs become weak over several seasons due to the decreased foliage.

There is also a Bacterial Leaf Spot (Bacterium tardicrescens) that is commonly mistaken as a fungal problem causing translucent spots that coalesce and involve the entire leaf. Normally found on Iris species.

Laburnum anagyroides is infected by the Leaf Spot (Phyllosticta cytisii). The leaf forms light grey spots with no definite margin and mature to brown. The black fruiting bodies appear as dots in the centre of the spot.

Leucanthemum species are infected by the leaf spot (Cerocspora chrysanthemi) and (Septoria leucanthemi).

Magnolia species are susceptible to many species including (Alternaria tenuis), (Mycosphaerella milleri) and (Phyllosticta species). Leaves generally turn brown from the apex or margins turning brown or spots appear on the leaf surface and leaves become yellow before withering and dieing. Normally the make the tree look poorly but have little effect on its growth. Control is not normally required.

Nerium oleander is susceptible to several fungal leaf spots including (Cercospora nerella), (Cercospora repens), (Gloesporium species) and (Phyllosticta nerii). Infected leaves should be removed but generally control is not required.

Nyssa sylvatica is infected by the leaf spot (Mycosphaerella nyssaecola) forming irregular purplish blotches.

Orchids such as Cattleya, Cymbidium, Cypripedium, Dendrobium, Epidendrum, Paphiopedilum, Phalaenopsis and Zygopetalum species are infected by several leaf spots including (Cerospora, Colletotrichum and Phyllosticta species). Normally forming dark or dead, circular or irregular areas on the leaves.

Palms such as Syagrus, Howea, Phoenix, Roystonea and Washingtonia species are infected by Leaf-scab (Graphiola phoeicis).

Palms such as Archontophoenix, Caryota, Chamaedorea, Cocos, Dypsis, Howea, Liculia, Linospadix, Livistona, Phoenix, Ptychosperma, Rhapis, Roystonea, Syagrus, Washingtonia and Wodyetia species are susceptible to several fungal leaf spots including;

(Bipolaris spp.), (Cylindrocladium spp.), (Colletotrichum spp.) and (Pestalotiopsis spp.).

Generally the circular leaf spots are brown and may have a yellow halo such as Palm Ring Spot (Bipolaris incurvata). They vary in size from small to large depending on the species. When a plant is healthy it recovers from attack, but heavy infections can defoliate, causing the collapse of the plant.

Palms are also infected by the Brachybasidium Leaf Spot (Brachybasidium pinangae). This fungus forms angular leaf lesions that produce fruiting bodies on the underside and is commonly found on Archontophoenix species.

                  Archontophoenix cunninghamiana

Passiflora species are infected with many types of leaf spot such as (Alternaria passiflorae).

Phoenix species are susceptible to False Smut (Graphiola phoenicis). This fungus forms yellow leaf spots that become hard with a raised with a blackish scab, which produces masses of powdery spores that are thread-like.

                  Pittosporum species

Pittosporum species are susceptible to the leaf spots (Alternaria tenuissima), (Phyllostica species) and (Cercospora pittospori). Circular or angular dark spots appear on the leaves and are surrounded by necrotic areas that are yellowish. Generally removal of infected leaves is adequate control.

Poa species and other cool season grasses are infected by Winter Fusarium Leaf Disease (Fusarium species), which causes small pale spots that are water soaked to appear on the leaves that turn red-brown. Infected leaves become bleached then wither and die, but the infection will not affect the crown or roots of the plant. It can be identified by pink, cotton-like mycelium and the plant prefers cold wet weather.

Populus species are infected by several fungal leaf spots including (Ciborinia bifrons, Ciborinia confundens), and (Mycosphaerella populicola).

Prunus species are infected by several leaf spots including (Cercospora circumscissa and Septoria ravenelii).

Pseudotsuga menziesii Douglas Fir is infected by the Leaf Cast (Rhabdocline pseudotsugae) Symptoms include the needles becoming yellowish at the apex and extending down the needle and spreading to others during moist spring weather turning them brown. Brownish scorched areas are noticeable on the tree from a distance. Control; is not normally required for mature trees but nursery stock may require spraying with a copper based fungicide.  

Psidium guajava (Guava) is infected by (Glomerella cingulate). This fungus courses spots to appear on leaves and mummifies and blackens immature fruit or rots mature fruit.  This fungus can devastate a guava crop.  

Quercus species are infected by several types of leaf spot including (Cylindrosporium microspilum) and (Marssonina martini). These attacks tend top take place later in the season and normally not detrimental to the tree.

Rhododendron species are infected by a large variety of fungal leaf spots including (Cercospora rhododendri) and (lophodermium melaleucum)

Salix species are infected by several fungal leaf spots including (Ascochyta salicis) and (Septogloeum salicinum).

Senecio species are infected by the fungal leaf spot (Alternaria cinerariae) and (Cercospora species), forming dark rounded or angular spots.

Spiraea species are attacked by the fungal leaf spot (Cylindrosporium filipendulae).

Stenotaphrum secundatum (Buffalo) turf grass is susceptible to Grey Leaf Spot (Pyricularia grisea) in domestic and commercial situations devastating lawns. This fungal disease infects the stems and leaves with small brown lesions that enlarge rapidly forming grey-brown spots that have darker borders or surrounded by yellow chlorotic areas. This infection is commonly found on newly laid turf but will also infect established lawns. It is most prevalent during warm humid periods in soil with a high nitrogen level.

Syringa species are attacked by up to six species of leaf spot including (Cercospora lilacis) and (Phyllostica species).

Syzygium species

Syzygium species are infected by fungal leaf spots but normally control is not required.

Tagetes species are infected by the leaf spot (Septoria tageticola), which starts at the base and moves progressively up through the plant, covering the leaves in grey to black spots.

Trillium species are host to several leaf spots, including (Colletotrichum peckii) (Gloeosporium Trillii) (Heterosporium trillii).

Ulmus species are infected by many fungal leaf spots including (Gnomonia ulmea) and (Cercospora sphaeriaeformis).

Veronica species are infected by the leaf spot (Septoria veronicae). The symptoms include small violet to brown spots appear on the upper surface of the leaf and correspondingly yellowish brown on the underside. The spots converge forming a scorched shot-hole appearance and eventually death of the leaf.

Vaccinium ovatum

Vaccinium ovatum is infected by the leaf spot (Rhytisma vaccinii) and (Dothichiza caroliniana).

Vicia species are infected by the leaf spot (Erostrotheca multiformis), which forms greyish spots that enlarge and may defoliate the plant.

Wisteria species are infected by three fungal leaf spots (Phyllostica wisteriae), (Septoria wisteriae) and (Phomatospora wisteriae).

Non-chemical Control

Remove and destroy infected plant material and avoid overhead watering.  When planting select infection resistant varieties. Practice crop rotation and add pot ash to the soil to decrease the plants venerability to the disease. Many species of fungus overwinter in fallen leaves, remove and destroy any litter under the plant.  

Winter Fusarium Leaf Disease in Turf Grasses can be minimised by aerating the soil, reducing thatch and avoid excessive nitrogen in the soil.

Chemical Control

Protective fungicides such as zineb or copper oxychloride should be sprayed at the first sign of infection and cuttings should be sprayed as they start to grow.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

DISEASE

   NAME

     Sclerotinia Rot, Crown Rot

     Sclerotinia species

Description

A fungal problem that attacks plant parts causing them to collapse and rot, including flower, leaf and stems.

Symptoms

This fungus attacks all the above ground parts of the plant but commonly infects the stem at the base, where it forms a soft, light brown watery rot that spreads rapidly. Under humid conditions the rotted areas forms white fluffy mycelium on which black sclerotia up to 10mm long develop.  These sclerotia also form within the stem in affected areas.  When leaves are infected the tissue may brown and dry out, especially during arid conditions.  The resulting affect of infection is the death of the plant.  

Image by B. Sonsie

Crown Rot (Sclerotium delphinii) causes leaves to turn yellow then become dry, and blossoms to wilt eventually killing the entire plant. It is found on Scilla, Viola and Delphinium species.

Flower Blight (Sclerotinia camelliae) infects flowers either by attacking the top of the petals forming brown specks or at the base of the flower where the petals turn brown then fall with out any sign of rot. The fungus develops on the fallen petals where microconidia are produced under moist conditions and eventually sclerotia appear. This form of the fungus can overwinter either above or below soil level until favourable conditions occur, then the spores are released and dispersed by wind.

Source and Dispersal

Sclerotia are found in the soil or on other infected plants and released spores are dispersed by wind.

Favoured Conditions

Prefers cool moist conditions with temperatures from 10º to 25ºC and is more common from autumn to spring when it is wet.  

        

Affected Plants

A wide range of plants can be infected included French beans, peas, celery, cabbage, cauliflowers, carrot, parsnip, dahlia stocks, primula and many weeds.

Actinotus, Dampiera, Westringa species and Helichrysum bracteatum are infected by the Crown Rot (Sclerotinia rolfsii). Basial rot of the plant with cottony fungal growth and is associated with root congestion. Certain species of orchid may also be attacked.

Allium species are infected by the White rot (Sclerotium cepivorum) which is a major fungal disease of plants.

The bulb rot  and are covered in mycelial which develop small black sclerotia (fruiting bodies) and infected plants may fail to produce flowering stem with the leaves become covered in a white mould, turning yellow then dieing off. It is commonly transmitted by infected seedlings and diseased plants should be burnt.  Avoid re-planting Allium species in the infected soil where the spores overwinter. Soil may be infected for several years.

Antirrhinum, Aquilegia, Lobularia and Mathiola species are attacked by the Stem Rot (Sclerotinia sclerotiorum ) which infects the stigma travelling downwards through the flower into the stem where water soaked areas appear causing it to collapse. The flowers become pale and the entire plant may collapse. On inspection flat sclerotia may be seen in the stem.

Camellia species may be infected by Flower Blight (Sclerotinia camelliae) which causes blooms to fall and Stem Rot (Sclerotinia sclerotiorum).

Hyacinthus species can be infected by the fungus Black Slime (Sclerotinia bulborum) that causes the leaves to turn yellow then fall and bulbs to disintegrate.

Iris species are infected by the fungus Rhizome Rot (Botryotinia convoluta) that infects the rhizomes and forms black sclerotia, and is normally found on dieing plants during spring.

Turf Grass in warm climates is susceptible to Rolf's Disease (Sclerotinia rolfsii). The fungus infects the turf causing isolated dead patches up to 450mm across from spring to summer. As it progresses the dead patches increase in size and the white cotton-like mycelium can be seen in the underlying soil. It is not regarded as a major problem, with minor attacks on Cynodon dactylon (Couch) and Zoysia species.

Non-chemical Control

Initially remove and destroy any infected plants, when replanting, avoid using susceptible crops for 3 years.  Space the plants to reduce the humidity and airflow and cultivate the soil to increase the drainage.  Remove weed growth and leaf or flower litter from around the base of the plants to reduce the development of spores

Turf Grass culture such as aerating soil and maintaining a neutral pH helps prevent infection of Rolf's Disease.

Chemical Control

No suitable fungicides available, though drenching or spraying the soil with the fungicide dichloran helps control it.

DISEASE

   NAME

     Grey Mould

     Botrytis cinerea, B. elliptica

Description

Grey Mold, Shoot Blight, Petal Blight is a fungus problem that generally forms water-soaked spots that rot and produces greyish sclerotia (fungal resting bodies) on the surface. They can be found throughout the year on dead tissue and on live material during under ideal climatic conditions. Damaged areas such as a tear in a leaf or an opening made by an insect are more likely to be infected.

Grey Mold on Begonia species

Image by B. Sonsie

Symptoms

The fungus attacks stems, leaves, flowers and fruit. In roses the fungus is primarily attacks the flowers producing pink rings on the petals and buds that become brown and rotten. This may extend down the peduncle to the stems causing dieback.

In other plants oval yellowish to brown spots appear, then the centre turns greyish and dries out and in humid weather the spots spread, joining up and infecting the entire leaf. This infection may also occur on the stems, and flowers may form abnormally or brown off and die.

When lettuce is infected it starts at the base causing a soft brown rot that may extend up the stem killing the plant, and pears flowers become infected then spreading to the fruit. This develops a sunken brown area that is soft and eventually is covered in grey powdery spores.  

                  Botrytis Blight on Senecio cruentus

Botrytis Blight (Botrytis tulipae) infects leaves, flowers and stems with flecks of brown spots that merge to form light grey rotted areas that have brownish margin that may destroy stems. Affected areas are covered in a grey mould during humid conditions. The spores overwinter in dark brown sclerotia, which are found on the outer scales of the bulb or at the base of the stem in Tulipa species.

Grey Bulb Rot (Rhizoctonia tuliparum), which infects the bulbs of Tulipa species, attacking the base of the leaves and rotting the bulb. When bulbs emerge during spring in infected soil's they soon die off. The greyish mold tends to be dry.

Source and Dispersal

The sclerotia (fungal resting bodies) are found on dead plant material or in the soil and remain viable for many years. The spores are dispersed by wind or splashing water.

Favoured Conditions

It prefers cool moist climate with morning dew.

Affected Plants

Grey Mold attacks a wide range of plants including roses, fruit trees, pelargonium, ferns, grapes and cyclamens. Heliotropium , Amaryllis, Lilium and Hippeastrum species  are also infected.

Agave species are infected by two fungal Leaf Blights (Botrytis cinerea) and (Stagonospora gigantea) that severely damage the leaves particular during wet periods or from excessive watering.

Cactus species are infected by soft rot or Grey Mould (Botrytis cinerea). Stems and pads turn are greyish with the upper surface, rotting then collapsing.  The dieing tissue becomes slimy and is covered with grey mould that develops black sclerotia, which propagates the disease.  It is more prevalent under warm humid conditions and control methods include removing infected parts and destroying them.  In glasshouse situations ventilation should be improved and watering should be restricted to create a drier atmosphere.

Cereus species and other cacti are infected by Grey Mold causing the segments to become discoloured and as the rot progresses it tissue becomes slimy and collapses. Black sclerotia forms on the affected areas that are covered in grey mold during humid conditions.

Cuphea species are infected by this blight.

Orchids such as Cattleya, Cymbidium, Cypripedium, Dendrobium, Epidendrum, Oncidium, Paphiopedilum, Phalaenopsis and Zygopetalum species are infected by Grey Mold or Petal Spot (Botrytis cinerea). Petal and flower stalks form small brown spots.

Paeonia species are infected by Botrytis Blight (Botrytis paeoniae) causing the leaves and flowers to form a grey mold then suddenly collapse and die.

Pseudotsuga menziesii   Douglas Fir is infected by Leaf and Twig Blight (Botrytis cinerea). This is a serious problem in wet conditions and is difficult to control.

Ribes species are attacked by Cain Blight (Botryosphaeria dothidea). The infection causes the cains to become blighted and wilt. To control remove damaged wood and destroy.

Non-chemical Control

Remove and destroy infected plants or fallen leaves. When planting, space as to allow good air movement to reduce humidity. Bulbs that are infected should be discarded and take care that bulb scales are removed from the soil to prevent further infection. Cactus and succulents that are infected should have the damaged areas cut out, or discard the entire plant. Under glasshouse conditions improve the ventilation and reduce watering to create a drier atmosphere.

Chemical Control

Under humid conditions spray regularly using a suitable fungicide such as thiram, mancozeb, dichloran and chlorothalonil.

Note

Always read the label for registration details and direction of use prior to application of any chemicals.

DISEASE

   NAME

     Spotted Wilt Virus

     Various Spotted Wilt Virus

Description

Viral problem that infects the leaves and stems of many plants.

Symptoms

Spotted Wilt Virus is a systemic disease that attacks a variety of plants with variable symptoms. In tomatoes young plants are particularly venerable, as indefinite mottling or rings first form on the upper surface of young leaves, eventually covering the leaf, causing it to shrivel and die. Stems and petioles or peduncles develop brownish streaks as the virus spreads eventually killing the young plants.

Pawpaw

Older plants that are attacked produce new foliage that is mottled with bronze colouring which soon turns black causing the leaf to shrivel and die. Stems can also be affected with brown streaks and fruit of an infected plant, ripens unevenly and is marked with circular blotches. This may cause premature fruit fall.

Spotted wilt also causes plants to become stunted and for flowers to develop reddish or yellow rings.

Fruit

Source and Dispersal

The virus is found on other infected plants and is spread by thrips, particularly Onion thrips (Thrips tabaci) and Western Flower Thrips (Frankliniella schultzei). The virus may also be dispersed in infected rhizomes or tubers or nursery stock.

Favoured Conditions

Hot dry weather favours thrips activity particularly during summer, spreading the virus which appears 2 to 3 weeks later.

Affected Plants

A wide range of vegetables and ornamentals are attacked include capsicums, potatoes, broad beans and

Amaryllis, Anemone, Antirrhinum, Aster, Begonia, Calceolaria, Calendula, Chrysanthemum, Dahlia, Gerbera, Lactuca, Lathyrus, Lilium, Lycopersicon (Tomato), Nasturtium, Papaver, Pericallis, Petunia, Phlox, Schizanthus and Zinnia species.

All have simular symptoms with yellowish wavy marks that spread causing the leaf to distort turn brown and die.

Other plants such as Zephyranthes species develop yellow or parallel streaks on the leaves that spread to the stems.

Non-chemical Control

Preventative measures are important for the uninfected plants by not planting near tomato crops and the removal of weeds. The controlling of thrip infestations greatly reduces distribution of the virus.

Chemical Control

There is no chemical control of viral problems.