Fungal diseases canker

Also known as valsa or leucostoma canker, this fungal disease can be a serious problem on trees. 

Tnink or branch crotches with swollen, cncked lesions. Cause Canker. This fungal disease attacks at the forks of branches, caus-mg swellings that crack open to expose the wood. The callus tissue that forms may also be affected. The canker can eventually girdle and kill the branch or tree. If the canker is small, cut out the tissue involved cut down and destroy seriously infected trees. Healthy trees are less susceptible. 

Valsa canker is a fungal disease that enters through injured bark. To prevent bark damage, make sure trees harden off in the fall by avoiding late-season fertilization or pruning. Also plant in well-drained soil and paint trunks with white latex paint diluted with an equal amount of water to reduce bark-damaging... 

Other fungal diseases cause swellings on plant parts, such as black knot of plum and cherry, or sunken areas in stems, as with Cytospora canker. On fruit, fungi can cause hard, black patches (scab), soft spots (rot), or fuzzy gray mold (Botrytis rot). 

Other fungal diseases which infect hops from time to time are canker (Gibberella pulicaris (Fr.) Sacc.), armillaria root rot (Armillaria mellea... 

AAL-Toxin. Stem canker of tomato is caused by the fungal pathogen Alternaria alternata f. sp. Ivcooersici (21). Concentrations of less that 10 ng/ml of AAL-toxin [14], a host-specific toxin, can produce disease symptoms. Two phytotoxic fractions have been isolated from fungal culture filtrates that reproduce disease symptoms in susceptible plants. These fractions are termed T ... 

Canes with discolored or dead areas. Cause Cankers. A number of fungal cankers attack roses. Pruning off and destroying diseased canes is the best approach to this problem. 

Shoots blacken, wilt, and die back. Cause Canker. Also known as dieback, this disease is caused by 2 fungal organisms and most often occurs during rainy weather. Prune and destroy infected shoots thin plantings to improve air circulation. Remove and destroy severely infected plants. If canker has been a problem, use preventive sprays of bordeaux mix. 

Diseases of plants may arise from attack by fungi, bacteria, viruses, insects or parasitic plants. Insects may also act as the vectors of plant diseases and provide routes for pathogens to enter plants. The disease may be manifest by decayed or swollen roots, shrivelled or lost fruit, chlorotic or wilting leaves, necrotic lesions on the stems, leaves or fruit, excessive gum formation or the formation of cankers. In this chapter we are eoncerned with the chemistry of the fungal attack on plants that lead to these symptoms. 

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