The main symptom of these anthracnose diseases appear as either; dead (dark coloured) spots, or sunken spots with a slightly raised rim.
Spots can be small or large.
Dark brown, purplish, red or black sunken spots appear on stems, fruits or seeds.
This disease may cause fruit drop and fruit rot....(Excerpt from page) Click to read more
| Blights, diseases that cause plant death
This is where parts of a plant (eg. leaves) stop growing and die, often without rotting (rotting may occur later).
A blight is generally sudden, and commonly involves death of parts of a plant, and sometimes dropping of leaves or fruit.
Types of Blights:
Blights are often named according to the part of the plant they infect and the plant variety they occur on: eg. Azalea Petal Blight is a blight where dead tissue develops on the petals of azalea flowers.
Control: Hygiene is most important for all blights.
Remove and burn all infected tissue as soon as detected.
Copper-based sprays will help control most blights, though some require other specific chemical sprays....(Excerpt from page) Click to read more
| Canker, isolated tissues dying on plants
A canker is a localised spot of dead tissue.
It often starts as a small but definite dead area, then spreads, perhaps girdling a stem.
This can then virtually "ringbark" a stem, killing growth further up. Cankers are caused by both bacteria and fungi.
They commonly develop from a damaged or wounded area of tissue.
If there is dieback from the tips of a plant, the cause may be a blight, or a canker which is "choking" the plant somewhere below the tip.
Citrus canker (ie. a bacteria: Xanthomonas campestris pv. citri), is one of the most serious citrus diseases, worldwide.
It affects most important commercial citrus varieties causing necrotic (ie. dead) spots or patches over the fruit, leaves and stems.
Fruit quality is impaired, and developing fruit drop from the ...(Excerpt from page) Click to read more
| Frost Protection
Many plants need to be protected from cold conditions. For some it’s a necessity – they won’t make it through a frosty winter without extra protection. Others will survive, but will grow much better with protection....(Excerpt from page) Click to read more
| GUMMOSIS | BLEEDING SAP FROM PLANTS
Gummossis is the result of diseases, or insect attacks where liquid (sap) oozes from a plant.
It is regarded as a secondary problem and indicates that the plant is under attack form some other source.
Only by controlling the pest or disease will the gumming actually stop.
Removal of the gumming may be necessary in order to get to the problem pest.
In many cases the gumming is the plant's defence system where it aims to suffocate, or drown, the problem pest in the plant's sap.
Gummosis of conifers is also known as resinosis....(Excerpt from page) Click to read more
| Leaf Spots, plant diseases
Leaf Spots are spots of dead or discoloured tissue on a leaf, often brown or black.
They are some of the most common diseases. Most leaf spots flourish after wet weather.
They rarely require attention, except at times when there is a serious outbreak.
Affected leaves should always be removed and sprayed though to prevent further infection.
A large range of different fungi and bacteria cause different leaf spots on different types of plants, including ones which cause other diseases (eg. Alternaria, Anthracnose and Septoria etc)....(Excerpt from page) Click to read more
| Managing Rots in plants
A rot is a disease which causes decay or disintegration of plant tissue.
The decay may be either dry (where the tissue remains hard), or wet (where the tissue becomes soft and squashy).
It may affect only one part of the plant (eg. fruit or roots) or the whole plant.
Rots can be caused by either fungi or bacteria.
Control: Chemical sprays can be used to prevent rots on fruits and vegetables. Damaged plant parts can be removed and destroyed....(Excerpt from page) Click to read more
| Mildews on Plants
These diseases cause young leaves and tip growth to become distorted and appear grey.
They commonly occur on azaleas, apples, cucurbits, and a wide range of other plants. There are three main types of mildew:
Causes a white powdery growth on the leaf surface.
Fungus grows over the surface of a leaf, seldom killing the plant but shading the leaf and reducing photosynthesis.
It generally starts in humid conditions (but not if leaf surface is covered with water).
Once started, it grows in almost any conditions. It most commonly grows on upper leaf surfaces, but also occurs below, and on other above ground parts.
It is a common disease on a wide range of both crop and ornamental plants, causing probably more losses than any other type of diseas...(Excerpt from page) Click to read more
| Natural Pest and Disease Control
There are three cornerstones to Natural Pest Control:...(Excerpt from page) Click to read more
| Phytopthora; cinnamon Fungus
Phytopthora cinnamomi, otherwise known as cinnamon fungus (and "die-back" in some cases) is a very serious fungus disease in both commercial crops as well as home gardens, and in some forest trees.
It infects the roots of plants and moves quickly through the plant tissue causing a thinning of the foliage, die-back and in many cases, death.
One of the worst aspects of this disease is that it affects a very wide variety of different plants...including many Australian native trees & shrubs, ornamentals, fruits, vegetables, ...there are thousands of different plants known to be susceptible....(Excerpt from page) Click to read more
| Plant Rust Diseases
Rust diseases are caused by a group of fungi causes rusty brown, orange or yellowish spots or stripes, normally on leaves and stems; but sometimes on flowers or fruit.
These usually occur as individual spots or stripes.
There are over 4000 different types of rust species. Most rusts are specialised diseases which affect only one type or group of plants (ie. Carnation rusts do not affect corn and vice versa).
Rust spores spread in the wind, by insects, by rain, by irrigation and by other animals.
Spores can blow into your garden from more than 100 km away.
Rusts Affects a wide range of plants, particularly grasses, grain crops (including corn), vegetables (beans & asparagus), pineapple, apple, coffee, carnations & snapdragons.
Some plants affected by rust...(Excerpt from page) Click to read more
| Plant Viruses
Viruses are small microscopic organisms which live inside the bodies of other organisms.
They are parasites and can have a wide variety of different effects on the organism they infect.
One of the most common symptoms in plants is a change of colour in leaves/and or flowers.
Infected leaves frequently show light green or yellow patches (ie. a variegated effect) due to interruption of chlorophyll production...hence photosynthesis is reduced.
This type of infection can cause reduction of crop yield or quality, or a general stunting of the plant....(Excerpt from page) Click to read more
| Scab Diseases
Scab is a general name for a disease that causes minor russeting of the plant skin tissue to more severe rough corky areas which may be pitted or raised.
Spots may be singular or join together to form larger lesions.
APPLE SCAB (Venturia inaequalis)
The same disease causes black spots on apple leaves and scabs on the fruit.
Infected fruit can develop deep cracks and grow into irregular shapes.
It is likely to occur if leaves remain wet at mild temperatures for 12 hrs or more (ie 13-16 degrees C).
It can be controlled by a regular spray program of copper-based sprays in early spring, followed by mancozeb, or zineb....(Excerpt from page) Click to read more
| Understanding Plant Health Problems
There are a wide range of things that can harm your plants.
The confined nature of small gardens may serve as an advantage or disadvantage.
Walls or fences can be a barrier to pests, diseases, and even undesirable weather.
These same walls and diseases can however, in other instances encourage problems.
They may restrict predators from moving into the area and attacking pests.
Diseases can be incubated and encouraged by poor ventilation, higher humidity and warmer temperatures that often characterize enclosed spaces.
If a plant is not healthy, and you want to determine what is wrong, you need to be systematic in your approach.
There are really only four broad possibilities. Plant problems can be grouped broadly into the following:...(Excerpt from page) Click to read more
| What are Wilt Diseases
WILT (Drooping foliage)
Plants lose their freshness and foliage droops because of a lack of water. Wilt diseases involve bacteria or fungi interfering with the supply of water to the plant.
Because the symptoms do not occur necessarily where the infection is, it is a lot more difficult to treat a wilt disease than many other diseases.
Often infection occurs through wounds or root hairs below the soil, so spraying the foliage may not help at all.
These diseases are some of the most difficult fungal diseases to control.
Plants Affected: A wide range of plants including deciduous trees, vegetables, flowers and various other plants....(Excerpt from page) Click to read more
| What causes Galls Swellings, Lumps, Cancer Like growths on plants
Galls are abnormal swellings, lumps or growths which can occur on virtually any type of plant tissue.
Galls can be caused by certain fungi, bacteria, insects or nematodes.
Crown Gall: Bacterial gall (Agrobacterium spp)
Large bumpy growths occur at the bottom of stems or trunks, sometimes on roots of plants, such as peaches, roses, grapes, apples, and dahlias.
Control: Destroy affected plants. Dipping plant material during propagation with fungicides, or in a weak bleach solution....(Excerpt from page) Click to read more
| What is Botrytis?
These are one of the most common type of plant diseases.
Also called "grey mould", they are serious, widespread diseases worldwide on flowers, vegetables, ornamentals, fruits and some field crops.
They are very common in greenhouses.
Mainly occurs on flowers or fruit, but can also appear as damping off of seedlings, stem cankers, spots on leaves, or rots of below ground parts such as tubers or bulbs.
Blossom blights often precede rots on other parts of the plant.
Flowers turn brown and rots, and the infection spreads to other plant parts.
In humid conditions a noticeable fluffy grey/brown growth is produced that is characteristic of Botrytis disease.
Plants Affected: Vegetables, fruits, ornamentals and some field crops....(Excerpt from page) Click to read more
| What is Damping Off?
Damping off is often seen as a rotting of young plants at soil level.
There are several fungi species causing damping off.
These include Pythium, Rhizoctonia, Phytophthora and Sclerotium.
This type of disease is common in seedlings and is a serious nursery problem.
Older plants are rarely killed by this group of diseases, however their growth may be considerably retarded by root damage.
Symptoms: Seeds can rot before germination, shoots from freshly germinated seeds can rot before they emerge from the growing media, or young seedlings rot at the base after they have emerged and collapse. On older trees, root and stem lesions and root rots may occur....(Excerpt from page) Click to read more
| What is Leaf Curl on Peaches?
Leaf Curl (Taphrina spp.) refers to diseases cause deformed leaves (and sometimes flowers and fruit) on several stone fruits & forest trees.
Peach Leaf Curl is a serious problem in commercial crops of peaches and nectarines.
Symptoms: Parts, or all of the leaves thicken, becoming distorted & curled.
Affected leaves can become red-purplish, and later turn yellow-grey. In severe cases, blossom, young fruits and stems can be affected.
This disease can seriously reduce the vigour of the plant. The impact of the disease is most noticeable in early spring, as the first leaves, burst from previously dormant buds....(Excerpt from page) Click to read more