Platycerium bifurcatum

PEST

 

   NAME

     Beetles (General)

     Various Beetle Species

 

   ORDER

     Coleoptera

 

Description of the Pest

There are many different types of beetles both adult and larvae feed and have chewing mouth parts.

 

Agave snout weevil (Scyphophorus acupunctatus)
The Agave snout weevil or sisal weevil is a beetle up to 15mm long. It has a dull brownish-black body with a long protruding snout and chewing mouth parts. The adult female lays eggs at the base of the leaves where the hatching larvae feed on the succulent centre of the leaf with their chewing mouth parts and cause significant damage. Decay microbes then entre through the wounds and cause the plant to die by collapsing from the base.

 

                  Brown (Scarb) Eucalyptus Beetle

 

Brown Eucalypt Beetle (Lepidiota rothei) adult is brown with hairy legs and grows to 20mm long. It has chewing mouth parts and feeds on the leaves, sometimes swarming and stripping the host tree. The lava is cream coloured curl-grubs that feed on the roots of the tree. The feeding habits of this beetle are very simular to the Christmas Beetle (Anoplognathus species), eating new shoots and leaves to the mid rib, commonly attacking Eucalyptus species.

                  

European Bark Beetle (Scolytus multistriatus) female adult is reddish up to 3mm long and lays its eggs in tunnels in the sap wood and the emerging lava tunnel through the bark forming tiny holes. This beetle is regarded as a main transmission source for Dutch elm disease that infects Ulmus species.

 

European Willow Beetle (Plagiodera versicolora) is metallic blue up to 4mm long and overwinters in the bark. During spring the yellowish eggs are laid and the emerging lava skeletonise leaves by feeding on the underside. There can be two generations per year and attack Salix species.

 

Fig Leaf Beetle         

 

Fig Leaf Beetle (Poneridia semipullata) is a dull brown adult has a reddish brown head and growing to 12mm (¼in) long with prominent antennae. It deposits up to 50 eggs that are in groups on the underside of the leaf. The yellowish spiny larvae are small and appear as sawdust on the leaf. As they mature they turn blackish and grow to 12mm (¼in) long, widest at the head.

It prefers coastal tropical to warm temperate regions and both adult and larvae feed on the leaves. The larva graze in groups skeletonising the leaves and making plants look unsightly.

 

Figwort Weevils generally the adult beetles are normally black to greyish white, up to 4-5mm long with one or two black circular marks where the wing cases meet. The larvae are yellowish to brown grubs with black heads up to 6mm long and have a slimy texture.

 

The larvae pupate in spherical cocoons that it spins and is attached to the host stems. The cocoon resembles the seed pods of Scrophularia species (Figwort). Adults overwinter in leaf litter or the soil emerging during spring and lay eggs on the host plant. There is normally two generations per year.

 

The larvae feed on leaves by grazing the surface of the leaf eating the epidermal layer. The leaf turns brown, shrivels and dies. Many plants are susceptible, including Hibiscus, Dahlia, Vitis species and avocados, potatoes, sweet potatoes, rhubarb, and various weed species.

 

   Paropsis species adult and larvae    

 

Leaf-eating Beetles in the Chrysomelidae family are found throughout the world with over 3,000 species in Australia. Generally small smooth and colourful, globular or flattened up to 15mm in length with antennae one third the length of the body. Normally adults and larvae feed on the living tissue of the leaves. There are many sub-families including Sagrinae containing the larges species, Bruchinae containing larvae that eat seeds and the larges subfamily Chrysomelinae contains many species such as Paropsis species. These beetles are characteristic dome shape and are commonly seen on Eucalyptus species.

 

Mountain Pine Beetle (Dendroctonus ponderosae) is a dark brown to blackish adult beetle up to 7.5 mm long. There are 4-larval stages that include a white larval with no legs that appear from vertical egg galleries and mature larval produce oval pupation cells towards the end of the tunnels in the tree. They emerge from small openings at the tunnel end as adults. This pest affects millions of hectares of forest in North America and Canada including many species of Pinus. It normally attacks older weaker trees but under ideal conditions it attacks healthy trees. Pinus albicaulis has become endangered due to the actions of this species. Numerous beetles can attack a single tree and the larval attack on the cambium layer can be accompanied with a fungal attack such as the Blue stain fungi (e.g. Ceratocystsis and Ophiostoma spp.) causing death of the tree. Symptoms include the needles in the crown wilt then turn orange-red for many months then become brown before falling to the ground. Pitch tubes can be located towards the lower part of the tree and consist of frass and resin.

 

 

Staghorn Beetle Damage

 

Staghorn Beetle (Halticorcus platyceryi) is a small rounded beetle that is black with four dull red spots on the wing covers. It has pinkish lava and both larvae and adult feed on the epidermal layer of fronds leaving small brownish sunken areas.

 

Wattle Blight (Paropsis orphana) adult is a light green oval-shaped beetle with white stripes on its wing covers up to 6mm long. The small lava has a tapering shape and both adult and lava feed together in groups on the surface of Acacia species leaves turning them brown.

 

Vegetable Weevil (Listroderes difficilis) is found during cooler weather (spring or autumn). The adult brown beetle up to 19mm long with a "V" mark on its back and the eggs are laid in the soil around the base of the host plant. The cream coloured lava emerges in spring after rain and feed on the lower leaves forming irregular holes or chewing holes in stems. The lava also feed on fleshy roots boring holes into carrots. Both the adults and lava cause damage, feeding on the plant during the night and resting at the base or under ground during the day. The lavae pupate in the soil over winter.

 

Life Cycle

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

 

Distribution of the Pest

 

Beetles are found world wide.

 

 

Period of Activity

The beetles are active from spring to mid summer preferring the warmer weather.

 

Susceptible Plants

The beetles attack many species of trees, shrubs, ferns and small plants as in potted plants in nurseries.

 

Anemone and Clematis species are attacked by the Black Blister Beetle (Epicauta pennsylvanica) which eats the leaves and flowers.

 

Callistephus species are attacked by the Asiatic Garden Beetle (Autoserica castanea) that chews on the foliage at night and hides in the soil or around the base of the plant during the day.

 

Carya species are attacked by the Bark Beetle (Scolytus quadrispinosus). The tiny adult beetle is brown up to 5mm long and the legless lava tunnel the bark and sapwood where it over winters, causing ringbarking. Twigs and small branches wilt and die.

This species is also attacked by the Twig Girdler (Oncideres cingulate), a reddish beetle that is 20mm long and produces small lava that girdles twigs by tunnelling, where it overwinters. This weakens the twigs causing them to snap off or results in ringbarking.

 

Cheiranthus species may be attacked by the Red Turnip Beetle (Entomoscelis americana) which is bright red with black markings in its head and wing covers and feeds on the foliage.

 

Eucalyptus species and other plants in the Myrtaceae family are attacked by the Flower Scarab Beetle (Protaetia species) a rounded brownish adult that grows to 20mm long, feeding solitary on flower pollen or new growth causing wilting and twig dieback. The insect is found from tropical to temperate regions and is regarded as a minor pest. Eucalyptus are also attacked by Leaf-eating Beetles which eat irregular pieces from the margins.

 

Damaged Margins on Eucalyptus by the Leaf-eating Beetles

 

Protea species are also attacked by the Flower Scarab Beetle.

 

Ficus species          Damaged epidermal layer

 

Ficus species are susceptible to the Fig Leaf Beetle (Poneridia semipullata). Both adult and larvae feed on the leaves eating the epidermal layer and making the plant in large infestations look poorly.

 

Ulmus species are attacked by the European Bark Beetle and the Leaf Beetle (Galerucella luteola) adult, which eats areas out of new leaves.

 

Ficus species are susceptible to the Fig Leaf Beetle (Poneridia semipullata). Both adult and larvae feed on the leaves eating the epidermal layer and making the plant in large infestations look poorly.

 

Samanea saman fruit pods are attacked when the burchid beetle (Merobruchis columbinus) oviposits in the immature fruit. The lava can kill or damage up to 75% of the seeds but is not commonly a major problem.

 

Solanum tuberosum is attacked by wireworm (Agriotes species). The larvae of this beetle, tunnels into the tubers.  It is best controlled by planting in the soil which has not been affected previously.

 

Ulmus species are attacked by the European Bark Beetle and the Leaf Beetle (Galerucella luteola) adult, which eats areas out of new leaves and its lava skeletonise the underside of mature leaves later in the season.

 

Damage Caused

Some beetles and their larvae may eat the leaf surface in bands leaving the veins intact while other larger beetles tend to eat leaves from the margins preferring new shoots.  

 

Beetle damage

 

Cultural Control

Small infestations may be removal by hand where possible.

The Brown Eucalypt Beetle will not fly during the night and if disturbed by shaking or beating the tree, fall to the ground where they can be collected on a tarp that is laid under the tree then destroyed. This method also works on the Flower Scarab Beetle that fall to the ground pretending to be dead when disturbed.

 

Biological Control

Beetles are eaten by predators including birds, frogs, and lizards and are attacked by parasitic wasps.

 

Chemical control

Will vary with the pest, the plant on which it is found. The part of the plant being attacked.

 

Note

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

Amendments by B. Sonsie Dip Hort Sc Burnley

PEST

   NAME

     Tip Borer

     Various Tip Borer Species

   ORDER

     Various

Description of the Pest

There is many species of moths which are brown, blackish or white up to 30mm long. Generally the fleshy, greenish to cream coloured larvae grow to 25mm long and are sparsely hairy. The Callistemon Tip Borer is laid by a metallic to blackish moth and the larvae are creamy grubs that have true legs. Some larvae are very active when disturbed such as the fleshy Macadamia Twig Girdler which has darker strips on its body and a dark head.

Dieback Borer Damage

Dieback Borer (Platyomopsis armatula) adult is a grey-brown beetle up to 20mm long with small lumps on its wing covers and long antennae. The 15mm long cream coloured larva tunnel under the bark and feed on the sapwood causing ringbarking. The entrance to the tunnel is covered in frass and plants in the Myrtaceae family such as Eucalyptus species are susceptible.  

Elm Twig Girdler (Oberea tripunctata). The adult beetle feeds on twigs causing girdling then deposits eggs during spring. The lava tunnels down the centre of the stem from the girdled point and overwinters in the tunnels. Twigs up to 14mm diameter may snap off at the damaged point and Ulmus species are normally the host.

Mahogany Shoot Borer (Hypsipyla grandella). The adult is a greyish-brown moth with a wingspan up to 45mm with the wings and veins distinctly overlayed in black. It deposits oval eggs that are tiny 0.50mm wide normally deposited in the leaf axil and change colour from white to red in the first 12 hours. In 3 to5 days the larvae emerges and can grow to 25mm long and is brownish white when young and maturing to bluish with a brown head capsule. Swietenia species are damaged as the larvae bore into the new shoots normally during spring or during the rainy season. The shoots and branches wilt then collapse. This is a major economic pest for cultivated trees.

Red Cedar Tip Moth (Hypsipyla robusta) adult is a grey moth with a wing span up to 20mm across and produces fleshy lava with true legs up to 20 mm long that tunnels into the tips of twigs. The tunnels are surrounded by webbing that is littered with pelleted droppings and is normally found on Toona species.

Staghorn Borer larvae grow to 15mm long and are greyish with true legs and the grey adult moth has a wingspan up to 20mm across. It attacks Platycerium species by eating tunnels into the sterile fronds.

Appearance and Distribution of the Pest

They are found mainly on the coast but also inland and are distributed by flying with the assistance of wind.

Life Cycle

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

Eggs are laid in bark on the growing tips. Larvae shelter in tunnels they create in the wood, up to 20mm deep.

Period of Activity

Active throughout the year in warm climates and are commonly found from tropical to sub-tropical and temperate regions.

Damage Caused

Generally the symptoms of tip borers is yellowing and curling of the leaves which wilt then die or shoots become blackened and are noticeable in the tree. Extensive feeding by a number of larvae causes dieback but normally, this is a minor pest.

The larvae emerge from their tunnels at night, to feed on the bark around the entrance holes. Entrance holes are covered by a layer of chewed wood fragments ("frass") and silk webbing. Most damage appears on twigs and new growth.

Typical larvae

The Callistemon Tip Borer tunnels down the centre of the twigs causing then to die or break off and the Macadamia Twig Girdler (Neodrepta luteotactella) form tunnels in sapwood that are covered in fine webbing that is dotted in brown excreted pellets. This is the same appearance as the Banksia Web-covering Borer (Xylorycta strigata) larva makes, as it tunnels down the centre of shoots.

Susceptible Plants

Many native and ornamental plants are susceptible to tip borers such as Callistemon, Melaleuca, Banksia, Hakea, Macadamia and Stenocarpus species

Eucalyptus, Callistemon, Corymbia, Leptospermum and Melaleuca species are attacked by the Dieback Borer (Platyomopsis armatula). Twigs and small branches are attacked and the larvae causes ring bark. Affected branches break easily in high winds.

Sambucus, Yucca and Delphinium species are attacked the Common Stalk Borer (Papaipema nebris) which attacks the stems causing the plant to wilt and topple over.

Cultural Control

Larvae may be destroyed after exposure by pulling away the covering pad of frass, or by pushing a length of wire into the tunnel. Damaged branches may be removed, or tunnels plugged.  Infested perennials or annuals should be removed and destroyed.

Biological Control

No effective biological control.

Chemical Control

Spray with Carbaryl (including the trunks or stems) if necessary while the insects are active.

Note

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

PEST

   NAME

     Common Slater

     Porcellio scaber

   ORDER

     Isopoda

   FAMILY

     Porcellionidae

Description of the Pest

Slaters are crustaceans; they are in the phylum Arthropoda and are related to prawns. They breathe through gills, which they must keep moist - therefore they favour dark, moist conditions. They feed on decaying vegetation. Slaters are oval in shape and relatively flat, their bodies appearing as a series of scale-like segments, with four or five pairs of jointed legs.

Adults are about 10-15mm long. They have a pair of tail-like appendages, and prominent antennae. Unlike the pillbug, with which they are often confused, they cannot roll up into a ball.

     

Appearance of the Pest

Slaters can be found in the leaf litter, compost heaps, and in most moist, sheltered locations. They are nocturnal and often go unnoticed, until their positions are disturbed. Adults live for two years; females can produce up to 60 young in up to three broods annually.

Period of Activity

All year round in temperate climates and under appropriate conditions.

Susceptible Plants

Slaters feed on decaying vegetable matter, but may also attack seedlings or the young roots of epiphytic plants (eg stag-horns, orchids etc). They may also attack the roots of plants that are already damaged. Slaters may be spread by transport of infested plants, compost or leaf litter.

Damage Caused

Slaters may actually have a beneficial effect, in recycling dead material. However, in conservatories, shade-houses, out-houses, and similar damp, moist habitats, they can damage seedlings and roots at the base of plants.

Control

Remove breeding sites by:

·        clearing rotten timber, decaying garden borders, infested leaf litter, etc); and

·        raising plants off the ground to improve air circulation and reduce moisture.

         Snail Bait (Methiocarb) will also deter slaters.

Note

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

PEST

   NAME

     Whitefly, Snow flies

     Various Whitefly Species

   ORDER

     Hemiptera

   FAMILY

     Aleyrodidae

Description of the Pest

This is a small sap sucking moth-like insect up to 3mm long with winged adults that have a covering of fine white powder, hence the common name. The wings are folded flat over the body and males live for one month and females live up to three months. The eggs are laid on the underside of the leaf and the wingless nymphs are immobile, flattened-round scale -like with a fringe of waxy filaments. The nymphs are translucent to greenish, congregating on young plant tissue and both adults and nymphs suck sap and producing honeydew.  

There are several species such as Ash whitefly (Siphoninus phillyreae), Tobacco whitefly (Bemesia tabaci), Silverleaf whitefly and Spiralling whitefly (Aleurodicus disperses)

Greenhouse whitefly (Trialeurodes vaporariorum)

This species of whitefly normally grow to 2mm long with two pairs of wings. Their colour is due to a covering of a fine white wax and the insect has a white-moth appearance. If disturbed the insects swarm and resettle on the plant quickly. The first nymphal stage is mobile and the later stage is scale-like with fine waxy marginal hairs. These nymphal stages produce honeydew, which encourages sooty mould. It is a persistent pest commonly found in glasshouses.

Adult                   Appearance under the leaf

The Hakea Whitefly (Synaleurodicus hakeae) is a small, moth-like up to 0.15mm wide with wings that have a powdery coating and produce flattened scale-like nymphs. Both adult and nymph gather together in colonies and suck sap.

Appearance and Distribution of the Pest

The eggs are laid during the spring and the adults tend to stay on the underside of the leaf until disturbed, when they fly in mass and may infect other plants. Many plants are only susceptible to this insect when cultivated under glass.

Life Cycle

This insect has a Hemimetabolous life cycle, ie. When the immature nymphs resemble the adults.

White flies have a gradual metamorphosis, egg and four nymphal stages. One generation occurs from three to eight weeks and is dependant on the current weather. Hundreds of eggs are deposited on the underside of leaves in arch or circles each with a short stalk.

Eggs laid in a pattern      Eggs laid in a pattern

After hatching the first nymphal stage wanders around on the leaf surface for several days. Then selects a place to suck sap where it goes through all nymphal stages emerging as an adult after the fourth stage.

Period of Activity

This peat is found from tropical to temperate regions and is most active during warm weather. It is difficult to predict an infestation, as some years it is severe and other years it is absent. In glasshouse conditions it is often a problem and may extend outside the normal period of activity. They overwinter in the egg stage or find sheltered places to hide.

Damage Caused

Affected plants have leaves with yellowish to white mottling on the upper surface or with shiny secretions on new shoots or on the underside. Heavy infestations cause leaves to wilt and sooty mould to appear on the honeydew. Plant looses vigour and in some cases die.

                  Tagetes erecta

Susceptible Plants

Whiteflies attack a wide range of plants affected by this insect, including Abutilon, Boronia, Hibiscus and Fuchsia species. Citrus, Vegetables, Ferns and certain weed species are venerable. Australian native plants are also attacked, such as the Hakea species.

Greenhouse whitefly (Trialeurodes vaporariorum) attacks a wide range of ornamental plants, weeds and vegetables including; Phaseolus (beans), Lycopersicon  (tomatoes), potatoes, Cucumis (cucurbits), Lactuca (lettuce), Dendranthema (Chrysanthemum), Dahlia and Hibiscus species.

Several ferns, including Adiantum, Asplenium, Davallia, Nephrolepis, Onychium, Platycerium and Pteris species are attacked with nymphs congregating on the underside of the fronds, normally causing little damage.

Rhododendron species are attacked by the Rhododendron White Fly (Dialeurodes chittendeni) causing yellowish mottled appearance on the upper surface of the leaf.

Cultural Control

It is difficult to control with out the application of chemicals, though strong jets of water greatly disturb the colonies. Companion plantings with basil or other aromatic plants deters white flies or spray the plants with onion-garlic spray.

In an enclosed environment sticky fly paper can reduce numbers. When the nymphal stage is found an application of white oil will reduce numbers.

Biological Control

A parasitic wasp (Encarsia Formosa) attacks nymphal stages reducing numbers. Other predators include small birds, spiders, ladybirds and there lava, hover flies, damsel flies and mantids.

Chemical Control

Plants may be sprayed with Dimethoate, permethrin, bifenthrin or pirimiphos-methyl, but some insects have immunity to chemicals. The pest may also be sprayed with a mixture of white oil and nicotine sulphate or pyrethrum.

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

     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

     Leaf Nematodes

     Aphelenchoides species

Description

These microscopic size soil borne nematodes attack leaves by entering through the stomates but are restricted by the veins. The nematode can resurface and move around the leaf in water, infesting other parts of the leaf.  

                 

Leaf Nematode (Aphelenchoides ritzema-bosi) enters the plant when the stems and wet allowing the nematode swim to the stomates in the leaf. The leaf forms yellowish to brown spots that are contained by the veins but merge eventually turning the entire leaf brown then dieing. It infects greenhouse and outdoor Chrysanthemum and Penstemon species.

Stem Nematode (Ditylenchus dipsaci) enters through the stomates in young shoots and working upwards as thew stem grows causing the leaves to become malformed. Flowers fail to open, stems may grow sideways and the plant becomes stunted, dieing prematurely. The main host is Phlox species but not all are affected.

Symptoms

Infested fronds of ferns turn brown to black and may die prematurely. Other softer foliage plants such as Chrysanthemums form yellow spots initially that are constricted by veins. These areas become dark brown turning black in severs attacks with the leaf withering and collapsing.

Source and Dispersal

The nematodes remain active in plant material for up to 18 months. They are dispersed by infected plant cuttings or soil and travel along a film of water on the outside of the plant. They can also be dispersed by splashing water from the soil or from another plant.

Favoured Conditions

Humid cool conditions are preferred, as in after periods of rain or following overhead watering. They also prefer over crowded fernery stock.

Affected Plants

A wide range of plants are affected these include, Australian native plants in the Asteraceae family or Anigozanthos and Lophostemon species. Ferns such as Asplenium, Blechnum and Pteris species are also susceptible.

Plumeria acutifolia

Many ornamentals, perennials, annuals, trees and shrubs are also attacked include;

Begonia, Bergenia, Chrysanthemum, Coleus, Cyclamen, Gloxinia, Impatient, Penstemon, Plumeria and Saintpaulia species.

Ficus and Philodendron species are occasionally attacked by the leaf nematode (Aphelenchoides fragariae) forming angular markings that are water soaked at first, and then turning brown appearing on the leaf surface.

Non-chemical Control

Heavily infected plants and infested parts should be removed and burnt. Infected plant parts may be immersed in hot water at 45 deg for up to 15 minutes. This can only be used in local infestations and the immersed period varies according to the species.

Be certain to propagate from uninfected plant material and avoid replanting with susceptible species.

Chemical Control

Application of a systemic pesticide such as Fenthion are effective, but must be used as soon as the damage appears and repeated fortnightly.

Note

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