Oedema - Camellia

'Oedema' is the term used for small corky brown or grey scabby areas on the leaves.  The affected tissue is hard and may occur on only a f[...]

Pestalotiopsis - camellia - Pestalotiopsis sp.

This fungus invades areas of leaf that are already sunburnt or damaged in some other way.  The area usually becomes s[...]

Petal Blight - Ovulinia azaleae

The buds and flowers are the only part of the plant affected by this fungal disease.  The disease is usually first noticed as circul[...]

Phytophthora root rot - Phytophthora ssp.

These fungi start by infecting the root hairs and rotting fine roots.  Rotting of larger roots and the stem base may follo[...]

Powdery mildew - rose - Oidium sp.

This fungal disease produces a fine white coating on the surface of leaves and buds.  In severe cases it also infects stems, part[...]

Powdery mildews

The term 'powdery mildew' applies to a group of related fungi.  Some of them can attack a range of different plants, while others attack onl[...]

Ray Blight - Chrysanthemum - Didymella Ligulicola

This disease shows up first as tiny dark-pink spots on the petals. It often starts on one side of the flower, causing t[...]

Ringspot - Camellia

This is thought to be caused by a virus but affected plants still grow and produce flowers normally. As the leaves age, the faint green rings develop[...]

Mosaic - Rose

This disease is cuased by a complex of viruses and is characterised by yellow patterns on the leaves.  Thesee patterns are variable and range from all[...]

Mosaic - Iris

This is a virus disease. On iries that grow from a rhizome, symptoms are light yellow-green streaks on the foliage. These streaks widen and brown and the l[...]

Leaf Blight - Umbrella Tree - Alternaria Panax

This disease is characterised by dark-brown to black patches on the leaves. These may enlarge to involve a quarter or more[...]

Leaf Gall - Azalea - Exobasidium Vaccinii

This fungus may attack leaves, flowers or seed pods, but symptoms are most often seen on the leaves. Whole leaves or parts of l[...]

Leaf Gall - Camellia - Exobasidium Camelliae

This fungal disease is able to infect the plant only when the leaves are extremely small. The fungus influences some of the [...]

Leaf Nematodes - Aphelenchoides spp.

These nematodes can live on the plant in moist areas around or in the junction between leafstalks and stem if the weather is dry. Th[...]

Leaf Scorch - Bulbous Plants - Stagonospora Curtisii

Daffodil and jonquil leaves may show symptoms soon after they appear above ground. The leaf tips are reddish-brown a[...]

Leaf Spot - Brush Box - Elsinoe Tristaniae

This fungal disease may be referred to as 'yellow leaf spot'. The spots, which are a dull fawnish-yellow, may grow to [...]

Leaf Spot - Chrysanthemum - Septoria spp.

The first signs of this disease are yellowish areas on the leaves, often near the edges. These become dark-brown circular spots[...]

Leaf Spot - Dahlia - Entyloma Dahliae

This fungus causes roundish spots of yellow-green on the leaves. These later go brown and dry out. The spots may be surrounded by a[...]

Leaf Spot - Eucalypt - Mycosphaerella spp.'

There are many different fungal leaf spots of eucalypts, but most are hardly noticed. However, there is a more noticeable[...]

Leaf Spot - Gerbera - Septoria Gerberae

This fungal disease is most likely to be seen in late summer or autumn. The spots begin brown to deep purple but develop grey to [...]

Leaf Spot - Grevillea - Placoasterella Baileyi

This disease is characterised by more or less circular black spots on the leaves. It can disfigure the plant but probably [...]

Leaf Spot - Indian Hawthorn - Entomosporium Mespili

This disease is characterised by round spots up to 10mm across. They develop a light-grey centre and a brown edge. Fu[...]

Leaf Spot - Iris - Cladosporium Iridis

This diseased first shows up as tiny brown spots, each with a watersoaked area around it. As these spots enlarge they turn grey an[...]

Leaf Spot - Ivy - Colletotrichum Trichellum

This fungus is most likely to be damaging in cool spring weather and on ivy plants growing in cool, damp situations or areas.[...]

Leaf Spot - Violet - Cercospora Violae

Violet leaves that are spotted are likely to have been infected by this fungus. This problem can be serious. If the disease is spr[...]

Lichens

Each of these plants is a symbiotic association of a fungus and an alga. The fungus shelters the algal cells and the algal cells produce food for the fungal cell[...]

Mistletoes

There are many different species of these parasitic plants. The sticky seeds are spread by birds. When they germinate, root-like growths are sent into the hos[...]

Infectious Variegation - Camellia

This condition is characterised by variable symptoms which include small yellow marks here and there on the leaves, groups of yellow ma[...]

Ink Disease - Kangaroo Paw

Black spots on stems and leaves may indicate a fungal disease. However, note that almost any type of damage causes black marks on these plants[...]

Fusarium Wilt - Carnation - Fusarium Oxysporum f.sp. dianthi

Carnation plants can be infected at any stage of their development. On older plants, this disease causes a b[...]

Fusarium Yellow - Fusarium Oxysporum f.sp. gladioli

This fungus is a soil inhabitant and is introduced into the soil in diseased corms which often look healthy from the [...]

Grey Mould - Botrytis Cinerea

This fungus produces sclerotia and may be present all year in pieces of dead plant material. A grey furry growth on the surface indicates s[...]

Downy Mildew - Rose - Peronospora Sparsa

This fungus causes purplish-red to dark-brown spots on the leaves. They are not uniform in shape, but many are angular. In humid[...]

Downy Mildew - Stocks - Peronospora Parasitica

This fungus causes yellow patches on upper leaf surfaces. The whole leaf may become yellow and die. The affected leaves wi[...]

Downy Mildews

The group called 'downy mildews' comprise a number of different fungi which cause similar symptoms on different plants. In general, patches or spot[...]

Fasciation

This abnormality most commonly involves the flattening of plant stems; instead of the stem being more or less round, it develops into a very much larger, flat[...]

Fire - Botrytis Tulipae

This fungus causes small brown spots on the leaves and flowers. The spots are most noticeable on light-coloured flowers. Spots spread to involve [...]

Fleck - Diplocarpon Mespili

On pear, the first symptoms, very small reddish dots on the top of the leaf, are seen in early spring. They grow and darken until they are al[...]

Flyspeck - Hibiscus - Microthyriella Hibisci

This fungal disease is more likely in humid areas or if the shrub is in a shady position in the garden.
The leaves gr[...]

Fusarium Bulb Rot - Lily - Fusarium Oxysporum

This fungus affects the bottom of the scales. These separate from the base of the bulb. Leaves that grow from infected bulb[...]

Cymbidium Virus

There are a number of viruses that infect orchids. The symptoms are often difficult to distinguish from one another. The leaf may have a mottled appearan[...]

Cypress Canker - Seiridium spp.

This fungal disease is usually noticed only when branches die back. Closer inspection will reveal a brown powerdy substance in splits in [...]

Damping - Off

The term 'damping-off' means death of seeds or seedlings wheen they are attacked by certain soil-inhabiting fungi or bacteria. If the rotting occur[...]

Dieback - Camellia - Glomerella Cingulata

The fungus that causes this disease can only enter the plant through a wound. The 'wound', however, can be a natural op[...]

Dodder - Cuscuta spp.

This is a parasitic plant. When dodder seed germinates in the soil a small seedling is produced. It elongates very rapidly and as soon as the threa[...]

Downy Mildews - Crucifers - Peronospora parasitica

This fungus causes pale green to yellow spots on the upper leaf surface. A furry growth appears on the lower leaf surf[...]

Downy Mildews

The group called 'downy mildews' comprise a number of different fungi which cause similar symptoms on different plants. In general, patches or spot[...]

Black Spot - Rose - Marssonina Rosae

This fungus causes black spots on the leaves. The spots, which may end up about 12 mm across, are more or less circular and have and[...]

Collar Rot - Rhizoctonia Solani

This soil-inhabiting fungus can cause root rots, stem rots, and crown or collar rots. It can attack many different types of plants and us[...]

Crown Gall - Agrobacterium spp.

This bacterial disease was previously thought to be caused by Agrobacterium Tumefaciens, which can be obtained from crown galls on any pl[...]

Anthrancnose - Rose - Sphaceloma Rosarum

The spots caused by this fungus may be watersoaked at first, but by the time they are noticed they are probably black with a ver[...]