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Mulberry Cankers



P_mulcanker

Mulberry Cankers

Usually appear in

Spring to Summer


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Caused By:-     Various Fungi and Bacteria

Description

This oicture is of the canker caused by Fusarium lateritium(Gibberella baccata). Picture by USDA Forest Service - Region 8 Archive, USDA Forest Service, Bugwood.org
The majority of canker-causing organisms are tied to a single host species or genus, but a few will attack a wider range of plants. This is the case with Mulberry Canker caused by Fusarium lateritium, which will attack many species such as apple, pears, hazelnut and citrus. The perfect stage of this fungus, i.e. the sexual phase in the life cycle in which spores are produced, is known as Gibberella baccata. With this disease shoots die back due to small cankers which girdle the stems on 1-year-old shoots. Tiny reddish-brown pustules, which are the spore producing bodies, develop around the infected area in summer. The death of the cambium in the infected area produce an L-shaped malformation of twigs. This disease also causes the disease called Mulberry bud blight.
Another canker in Mulberry is Sooty canker is caused by the fungus Hendersonula toruloidea(Nattrassia mangiferae). (This fungus is also known as a pathogen in humans so care should be exercised when handling). Mulberrys are very susceptible as are ash, citrus, walnut, fig, wisteria, sycamore, apple, apricot, poplar and other smooth or thin bark trees. Sooty canker causes cankers which girdles the branches causing wilting and dieback. Leaves on affected branches are often small and wilt and die during the summer. Brownish, moist areas appear on limbs during the first stages of disease, and the bark in these areas cracks or peels away revealing black masses of fungal spores. The bark and sapwood around the spore mass is stained dark brown to black and cambium under and around the canker is killed.
Mulberries can also be attacked by other canker causing organisms.
See these other Cankers Apple and Pear, Bacterial, Bleeding, Canker, Cytospora, European, Horse Chestnut Bleeding, Parsnip, Pear and Apple, Phomopsis, Poplar Bacterial, Rose Stem and Dieback, Willow Black.


Control

Canker and anthracnose are general terms for a large number of different plant or tree diseases, whichhave similar symptoms including the appearance of small areas of dead tissue, which grow slowly, often over a period of years. Some are of only minor nuisance, but others are ultimately fatal to the tree. Some are of major economic importance in agriculture and horticulture. Different cankers and anthracnoses are caused by a wide range of organisms, including fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms only attack a single host species or genus, but a few will attack a wider range of plants. Canker and anthracnose can be spread by weather and animals, making an area that even has a slight amount of canker hazardous to other uninfected areas.
With both these cankers the fungi infects the tree through cracks in the bark or wound sites caused by heat stress, sunburn, pruning or freezing. Trees with smooth bark that is easily wounded are particularly susceptible. Infection is thought to take place during mild wet weather in the winter months. Fungal spores easily move from one infection site to another by wind and rain, and animals to infect new trees.
With Sooty Canker the fungus grows into the bark where it becomes established and produces masses of black spores for which the disease is named. It is well adapted to hot, dry weather, and progresses faster in stressed trees during hot summers.
Disease can be prevented by maintaining tree vigour and avoiding unnecessary pruning or wounding. Sunburned bark is the most common point of entry for fungal spores, and careful pruning techniques should be used so that limbs that shade the trunk and scaffold branches are not removed.
With Fusarium Canker when infections are found in upper branches, remove infected limbs by cutting at least six inches below infection sites. If severe pruning is needed, be sure to remove limbs in the fall or early spring when the remaining tree will not be sunburned as a result of pruning.
Remove all infested plant material from the site and burn since they are a source of spores.
Some cankers are treatable with fungicides or bactericides, but many are not; often the only treatment available is to destroy the infected plant to prevent the disease from spreading to other plants.

P_mulcanker P_mulcanker2

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