Canker disease

Diterpene phytotoxins sphaeropsidins A—F, tri- and tetracyclic unrearranged pimarane skeleton, are isolated from Sphaeropsis sapinea, a fungus that causes a canker disease of Italian cypress. Sphaeropsidin A is the major toxic substance showing nonhost-selective phytotoxic activity326 (Figure 36). 

Several species of Seiridium, including S. cardinale, S. cupressi and S. unicorne, are associated with the canker diseases of cypress, Cupressus sempervirens. The phytotoxic metabolites include the butenolides seiridin (8.61) and isoseiridin (8.62) and their 7 -hydroxy relatives as well as the sesquiterpenes seiricardine A (8.63) and B (8.64). Solutions of these sesquiterpenes when applied to leaves produce chlorosis, browning and death of the leaves. 

The genus Alternaria is widely distributed in nature, and a number of Alternaria spp are pathogenic to plants (66). A. alternata f sp. lycopersici was isolated from susceptible asc/asc) tomatoes with stem canker disease (33,40, 48). The active phytotoxin responsible... 

AAL-toxin was first described as the active component of A. alternata culture filtrates that cause stem canker disease in asclasc tomatoes (Lycopersicon esculentum Mill.) (39). At that time, because heterozygous (Asc/asc) and dominant (Asc/Asc) genotypes were resistant to AAL-toxin, it was felt that it was a host-specific toxin (33). 

Grogan, R.G., Kimble, K. A., andMisaghi, 1.1975. A stem canker disease on tomato caused by alternata f. sp. lycopersici. Phytopathology 65 880-886. 

It is far superior to any other known remedy for the cure of all diseases arising from impurities of the blood, such as Scrofula, Rheumatism, Cancerous Humors, Erysipelas, Canker, Salt Rheum and Skin Disease. ... 

Signs Plants infected with citrus canker have characteristic lesions on leaves, stems, and fruit with raised, brown water-soaked margins usually with a yellow hallow effect around the lesion. Incubation is typically 14-60 days. Older lesions may fall out, creating a shot-hole effect. Fruit production declines and then stops. The disease ultimately kills the tree. 

Sphaeronema. This disease, mainly a trunk canker, was first described in Ecuador in 1918 by Rorer and was attributed by him to Sphaeronema fimbriatum, better known currently as Ceratostomella fimbriata. It has also been reported to cause a pod rot. 

It is reported that in Venezuela (26, 36) this disease occurs in epidemic proportions in certain areas and causes serious trunk injury to 3 to 5% of the trees. It also occurs probably in other areas of tropical America. In Ecuador this disease is called machete disease, because the fungus, a wound parasite, infects through cuts and produces severe cankering in the trunk. No chemical control has been attempted, and burning the infected trees is the only control used at present in Venezuela. 

Disease and/or pest resistance If you have a particular local problem, such as nectria canker, seek suggestions and advice on resistant or less susceptible varieties. 

What to do Prune out affected branches and remove fruit from the tree. Pick up windfalls. Do not compost any of this material. Take care not to damage fruit that is to be stored. Do not store any diseased fruit. Prune out cankers and diseased spurs. 

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

Tomato canker caused by Xanthomonas can be controlled by the application of tetracycline(52-53). Streptomycin resistant strains of bacteria have Been found on peach, tomato and peppers(54), and the mixture of two antibiotics has helped to stop tHe build-up of resistance in the patho -gens in some cases(55-56). The silvery disease of sugar-beet caused by Coryn 5actferium is insufficiently controlled by mercurial compounds, but is completely eliminated when seeds are dipped for several hours in a solution of streptomycin. 

The control of bacterial diseases with the currently available products Is very unsatisfactory. The problem has become urgent with the spread of fire blight (Erwlnla amylovora) In Europe, and the Increased Incidence of bacterial leaf blight of rice (Xanthomonas oryzae) and citrus canker (Xanthomonas cltrl) as well as many other bacterial diseases. The direct control of virus diseases Is cur-... 

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 ... 

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. 

Cane dieback. Causes Blueberry cane canker Fusiccsccum canker. Blueberry cane canker, most pre alent in the South, shows up as reddish, conical stem swellings. The next year these swellings become blisterlike, light gray, and then black and fissured. If this disease is a problem in your area, plant rabbiteye blueberries, which are not susceptible to cane canker. Or plant highbush cultivars resistant to cane canker, including Atlantic and Jersey . 

Trunk with brown patches exuding a thick, amber gum. Cause Brown rot gummosis. Eventually brown patches form dark, sunken cankers. Lower branches above the canker may wither and die. This disease begins when... 

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