Index: ABCDFGIMNPRS
Disease
Azalea Petal Blight is caused by fungus and is a problem move common in warm humid areas like Sydney. It ruins our wonderful display of spring flowers.The petals develop spots, brown on the white flowers and cream on the coloured flowers. Soon the petals turn completely brown, collapse and die. The flowers remain on the stems.
Azaleas
As with many fungi there is no cure and cultural and preventative steps need to be taken to control the disease.It is really important to remove and destroy all the infected flowers as the fungal spores remain within the collapsed flowers until the following year when conditions are again favourable.Avoid overhead watering.There is a preventative fungicide called Zaleton that will help control the fungus. You need to start spraying the flowers as soon as the buds emerge and continue to do so every two weeks until the flowers have finished. Like many chemicals this has toxic side effects, so read the safety sheets. Not recommended to be used by women when pregnant or trying to become pregnant Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Blackspot inn apples is caused by a fungal disease (Venturia inaequalis Black patches on leaves and fruit which can cause both to grow in a distorted form. It is a disease that becomes worse with a combination of high temperatures and lot of rain.
Apple trees
Remove diseased fruit and leaves by hand and destroy.Lime Sulphur can be used during the dormant period to late bud swell. ( Do not use later as can restrict growth)A systemic fungicide like Triforine can be used as a preventative spray within three days of warm rainy weather.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Black and irregular and sunken patches on citrus fruits particularly Valencia Oranges.
Citrus
Spray with a copper based fungicide at petal fall. The copper forms a barrier to prevent the fungal spores attaching, so spray prior to infection. The copper remains on the surface we will need to be reapplied if the conditions are wet. Do not apply to much copper as this can damage the fruit.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
A fungal disease (Diplocarpon rosae) that forms on rose leaves and stems displaying as a growing patch of purple to black. Eventually the leaves will die and drop off. It is worse in warm humid conditions
Roses
Choose more resistant varieties.Collect any diseased leaves and prune away badly diseased part of plant,place in the garbage as the spores will remain long in your garden to re-infect other healthy plants. Avoid watering overheadDuring early spring spray plants with either a fungical soap or wettable Sulphur, reapply regularly and after rain.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Although plants require very small amounts of Boron. The effects caused by a lack of Boron can be quite dramatic. As gardeners the time we see it most is when we are growing vegetables. Cauliflowers can the flower head may not develop properly or the stalk develop a hollow stem.Beetroots will often develope roots with a distorted surface and dark rough patches. Other root crops like turnip and swede can also develop hollows within the root.
The key to successful growth of vegetable susceptible to boron deficiency is to add boron to the soil at the time of planting. Boron is commercially available as Borax - do add too much use only 2g per sqm and mix into soil before planting the seedlings.It is important to know that many vegetables don't like too much boron and may not grow well in beds where boron has been added. Avoid planting potatoes, tomatoes, french beans, celery and certain members of the cucurbitaceae family.
Botyritis Blight affects Marigolds (Tagetes) in late summer and autumn and in other periods of high humidity. Sometimes known as Grey Mould, it will decimate a plants in a relatively short time.
The foliage will turn blotchy grey and the blooms will decrease in size and start to rot, tending to die off quickly as the plant cannot transfer enough energy through he foliage.
You can try to spray with Garlic laced water or Neem Oil. Better to remove the entire plants and any foliage debris surrounding, put it in a bag and burn or dispose of in garbage., taking care not to shake any off to re-infect other plants.
It displays as small cankers on branches and stems which exude a sticky gum. The blossoms turn brown, wilt and die. The fruit show small brown patches with light brown powdery spores on them, within 3-5 days will be completely rotten.
Stone Fruit
Prune away infected areas of plant. Remove all infected fruit and destroy. Avoid overhead watering. Check best time for pruning and prune to create a shape that allows for good air circulation and access to sprays.Use a preventative fungicide at Leaf Curl Copper Fungicide, Gk Copper Spray + white oil.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
This is a fungal infection. The leaves become pale, swollen and enlarged, eventually the lower epidermis splits releasing spores into atmosphere. (see GardensOnline Blog for more photos)
The affects the new leaves of Camellia (and sometimes Gardenia) during the spring. It will not affect older leaves so does not affect the whole plant
There is no chemical solution. It is important to cut off and destroy the infected leaves before the epidermis splits and releases the spores.
This is caused by a soil inhabiting fungus (Rhizoctonia solani)Young plants show a shrivelling of the stem at soil level and the plant collapses, turns brown and dies. This tends to be a problem in warm weather of late spring and autumn
tomatoes, many veggies, seedlings and cuttings.
Remove infected plants the soil around them and destroy. When planting do not plant too closely together to allow air to circulate around stems. Do not over water. Use fertilisers - healthy plants are better able to recover from the disease.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Collar Rot is caused the fungus Phytophthora citrophthora This tends to affect citrus trees especially when they are young. It is often associated with poor drainage especially after long periods of wet and humid conditions. It can also occur if watering system has been directly at the base of the tree or the base has been surrounded by too much mulch.The first indication that there may be a problem occurs when the bark at the base of tree starts to turn black, this may be accompanied by gum oozing from the area. The tree will then show other signs of stress, leaves turning yellow, dieback and general loss of vigour.
Citrus trees - particularly 'Eureka' and 'Lisbon'
Prevention is the best solution. Make sure that the tree you have purchase has been grafted onto resistant stock Poncirus trifoliata or Citrange hybrids'Troyer' and Carrizo'Before you plant the tree check soil is well drained. Once planted keep all weeds and other plants aways from the base; do not cover the base of the tree with soil and mulch; cut any low branches to encourage good air movement around treeIf it is too late and you have a tree that is affected. Your course of action will depend on how much of the crown has been infected. If more than half has been infected then remove and destroy the tree. If less than half is affected you can scrape away the infected material and paint with a curative fungicide. At the same time you need to improve the drainage, remove mulch and weeds from around the base and keep watering away from the trunk.
This is a fungal disease of seedlings. There are three fungi that have been implicated Pythium spp, Rhizoctonia and Phytophthora spp. It is influenced by the poor drainage of the potting mix, over watering and oversowing.The seeds germinate and seem healthy, the plant stem starts to rot near the soil surface, the plant wilts, falls over and dies.
Seedlings
Improve the drainage and air filled porosity of the growing media by using a course seed raising potting mix. Before you start ensure that pots, benches and tools have been treated with disinfectant.When sowing your seeds try not to over sow them, if using very small seed they can be mixed with sand for better distribution.Follow advice on pack for best time to sow seedsReduce the moisture levels in the soil by always watering before noon.
Is first seen on the leaves as small light yellow spots or white, these become bigger and covered with white fungal threads (downy patches). which stunt growth. In some plants the new leaves can become distorted. This can be caused by various fungi each specific to a small range of plants. As wit all fungi they prefer warm humid coniditions.
Cucumber, pumpkin, lettuce, cabbage, cauliflower, leak, pea, onion, swede, grapes, roses and stock.
In humid areas aim to choose less susceptible varieties. In humid areas make sure the plants have lots of air around them to reduce the levels of humidity around the plant.Prune and destroy all infected leaves immediately.Plants can be sprayed or dusted with sulphur every week and after rain. Do not use sulphur when it is very hot or the plant is distressed. There are some systemic fungicides that can be used, check labels for suitability with your plants.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Galls are usually hard brown and irregular in shape and covered with a rust coloured powder, they can vary in size from a few millimetres to almost 10cm. A Gall is the plant's response to tissue damage caused in this case by fungi. The look will depend on the species of wattle and where the infection has occurred. The infecting organism is a species of Uromycladium and is specific to certain species.
Infection can occur in the phyllodes, leaves, pods, stems and branches of different species of Acacia.
Gall tend to occur in plants that are stressed often due to soil conditions. Once you have cut away any plant tissue infected with gall try to improve the growing conditions of the plant. There are no chemical solutions for this conditions
This is a persistent, soil inhabiting fungus ( Fusarium oxysporum) which enters the plant through the roots and effects the sap channels. It starts with a browning off of leaves and a rapid wilting of the leaves and branches. There are different types of this fungi and each affects specific plants
Tomatoes, cucurbitis, carnations, gladioli
Once its in the soil its tricky to eradicate.Remove and destroy any infected plants.Plant to allow good airflow between plants.Practice crop rotation - allowing a 4-5 year cycleSome people recommend covering the whole area with black plastic (held down with bricks all round) in order to heat the soil to high enough temperatures to kill the spores. You'll need to keep it there for a few weeks in sunny weather in order to ensure its fully cleansed. Once you have done this you can plant your crops.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Grey Mould is a fungal disease most commonly seen on flowers and fruit of roses during periods of high humidity.Infected flowers first display small rings on the petals, these tend to be red-pink on white flowers and grey-brown on darker flowers. As the fungi spreads the flowers become covered in a grey furry growth, the flowers remain attached becoming slimy before drying out. The spores remain on the dead plant material over the cooler months and germinate as the humidity increases.Photo Gemes Roses
Firstly reduce the humidity and improve air circulation around the plants. For roses to grow well they require a minimum of 6 hours sun a day, good air flow around the plant and no overhead watering. Aim to plant your roses approximately a metre apart. When pruning your plants prune the stems to outward facing buds create a vase shape and improve the air flow through the plant. Always water in the morning and avoid wetting the leaves, a drip watering system or wand hose attachment allow the base of the plants to be watered leaving the above ground parts of the plant dry.Remove and destroy any infected flowers immediately, make sure secateurs are cleaned before and after so as not to transfer spores to other plants.Chemically this is a difficult disease to control as the mould has become resistant to many fungicides and others are no longer available.Note: Many chemicals sold can be harmful to other insects as well as some animals and in some cases, humans. Always read the manufacturers instructions and warnings before you begin and use as directed.
The leaves, initially the new growth, turn yellow whilst the veins remain green, this effect is known as chlorosis. The most likely cause is that the soil is too alkaline; at high pH the plant cannot absorb the iron the soil. Other causes may be over watering, drought and in spring a big difference between the air and soil temperature - this will improve as the soil temperature increases.
All plants
Check the pH. If the soil is too alkaline add Sulphur. If the soil pH is neutral use chelated iron either as a foliar spray or directly to the soil.Note: Always read the manufacturers instructions and warnings before you begin and use as directed.
Magnesium is a key component of chlorophyll (green of leaves). Lack of Magnesium shows the older leaves. The Magnesium the older leaves moves (translocates) to the growing tips to help the plant produce new leaves. The sides of the leaf turn yellow and spread towards the tip leaving an inverted arrow of green at the base of the leaf.Chlorophyll is necessary in plant's production of Sugars (photosynthesis). Lacking in Magnesium leads to a loss of vigour in the plant.Plants take up Magnesium and other nutrients from the soil. The less Magnesium available in the soil the less the plant can take up through its roots. The uptake of nutrients can be affected the pH, water content and temperature. There are times when there may be nitrogen in the soil but plant is unable to use it because the temperature is too cool, there is too much or too little water and/or the soil pH is too acid or too alkali.
All green plants
Before adding Magnesium in the form of a Epsom Salts check that the soil is not too dry/wet, the pH is neutral. In early spring the soil may still be cold by comparison with air temp, this can lead to the upper parts of the plant using more nutrients that the roots in the cold soil are able to take up. If this may be the case you will just have to wait until the soil warms up.
Myrtle rust is a serious fungal disease which was first detected in Queensland in 2010. First signs of myrtle rust infection are tiny raised spots or pustules on infected leaves. After a few days these pustules turn a distinctive egg-yolk yellow colour. The rust poses no threat to human or animal health.
Myrtle Rust affects plants belonging to the Myrtaceae family including Australian natives like Callistemon, Tea Trees, Melaleuca, Corymbia and Eucalypts. Popular garden plants like Austromyrtus inophloia syn.Gossia inophloia are also susceptible.
Do not move the infected plant material to avoid spreading the disease, and report all suspect plants immediately to your local state exotic pest hotline - 1800 084 881.
Nitrogen is a key component of chlorophyll (green of leaves). Lack of nitrogen shows up in all leaves, they become paler and the lower leaves turn yellow. Chlorophyll is necessary in plant's production of Sugars (photosynthesis). Plants that are lacking nitrogen not only have pale leaves but also a reduced the vigour.Plants take up nitrogen and other nutrients from the soil. The less nitrogen available in the soil the less the plant can take up through its roots. The uptake of nutrients can be affected the pH, water content and temperature. There are times when there may be nitrogen in the soil but plant is unable to use it because the temperature is too cool, there is too much or too little water and/or the soil pH is too acid or too alkali.
All green plants.
Before adding nitrogen in the form of a nitrogenous fertiliser check that the soil is not too dry/wet, the pH is neutral. In early spring the soil may still be cold by comparison with air temp, this can lead to the upper parts of the plant using more nutrients that the roots in the cold soil are able to take up. If this may be the case you will just have to wait until the soil warms up.
This is a disease caused by the fungus Phytophthora infestans The leaves develop dark marks, the leaves soon shrivel and turn brown. The stems may develop brown lesions. The tomatos develop dark patches and the mature fruit start to decay as it ripens. The potato tuber develop a reddish-brown decay below the skin and the tuber starts to rot. Like all fungal diseases blight it always worse in warm damp conditions.
Affects potatoes and tomatoes.
All disease plant material should be removed and destroyed. Harvest potatoes early to avoid infection. Keep plants well fed and remove excess leaves to allow a good air flow between plants. Once established it is hard to treat. Spray with a protective copper based fungicide (Fungus Fighter Copper Fungicide). Spray with sulphur or systemic fungicides as soon as symptoms appear, respray as per manufacturers instructions.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
This is caused by a variety of fungi, all have the same life cycle, cause similar problems and are treated in similar ways. Each fungi attacks a specific range of plants. Infection shows as a white powdery growth on leaves flowers and twigs. Leaves may turn yellow and drop. As with all fungi they prefer warm humid conditions.
Pumpkin, squash, marrow, cucumber, roses, peas, turnip, strawberries, aster, poppy, zinnia, pansy, delphinium, roses, apple, begonias, hydrangeas and eucalyptus seedlings
The best solution is to introduce fungus eating ladybirds (Illeis galbula) which are bright yellow and black. Otherwise remove and destroy all infected leaves and stems.Space plants a sufficient distance apart to allow for good circulation of air.Spray with sulphur or systemic fungicides as soon as symptoms appear, respray as per manufacturers instructions.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
Is caused by the Phythophthora fungus that lives in moist soils.This tends to be a problem of poorly drained and saturated soils. It is a problem seen in both indoor and outdoor plants. It is one of the biggest killers of indoor plants and caused by over-watering and insufficient drainage.The fungus enters the roots via the root hairs and destroys the roots vascular tissue. The healthy creamy white roots become brown and brittle as they die. The plant is less able to take up water and develops signs of water stress: yellowing leaves, wilting, leaf drop and branch die-back. In hot conditions the plant may die quickly.
A wide range of plants including strawberries, carnations, come cypress species and wide range of Eucalyptus and Oleanders.
If the problem is pick up before the majority of roots have been affected the plant may be saved by improving the draining, avoiding over watering adding organic material to the soil and making sure that any mulch or weeds are kept away from the base of the trunk.In many cases the plant cannot be saved and the only option is to remove and destroy the plant. If you are getting rid of an indoor plant make sure that you throw the soil with the plant.When it is time to replace the plant choose an phytophthora resistant species.For plants with a reasonably functioning root system then a systemic fungicide like Fongarid can be applied. The key being that the roots must be able to take up the fungicide.
This is a fungal disease of the stems. The stem below the pruning cut turns brown and dies back to either a large bud, branch stem or in less resistant varieties to the base killing the whole plant.
The fungi enters the plant through pruning wounds or damage to the stem. It is important that clean sharp secateurs when pruning roses.Remove infected stems to well below the dieback and to a branch node. Fertilise to encourage healthy growth.
Rust is a term used to cover various fungal diseases on various plants. Depending on the type of fungi the pustules on the leaves can vary from yellow/ orange to reddish/purple. When the pustules open they release masses of tiny spores. The leaves tend to die early and drop prematurely.
beans, beetroot, silverbeet, spinach, anthurium, azalea, boronia, calendula, daisies, roses, chrysanthemum, some stone fruit, geranium, fuchsias.
Choose fungal resistant varieties. Grow plants in a sunny spot and allow space between each plant to allow air to circulate. Keep weeds away from plants, avoid overhead watering. Remove and destroy all diseased leaves. Spray with sulphur or systemic fungicides as soon as symptoms appear, respray as per manufacturers instructions.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
The fungus grows in the 'honeydew' secretions of various insects, scale, aphids and mealybugs. The fungus is thick and black and stops light getting to the leaves so reducing the plants ability to photosynethise.
Any plant with honeydew on leaves.
Remove the source of honeydew. Once mold dry it will start to crack and flake, it will either wear off in time or hosing can help. There is no need to apply fungicide as the Sooty Mold will disappear once honeydew problems has been treated.Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.