Alternaria diseases

China is the largest producer the average yield of ginseng per acre is only two thirds of what could be reasonably expected. This shortfall is caused almost entirely by diseases that attack the crop.12 Fungus diseases like Alternaria panax, Fusarium spp., Phytophtora cactorum, and Cylindrocarpon destructans can devastate ginseng cultivations. 

Brammall, R.A. Alternaria blight. In Diseases and Pests of Vegetable Crops in Canada. Howard, R.J, Garland, J.A., Seaman, W.L. ed., The Canadian Phytopathological Society and the Entomological Society of Canada, Ottawa, ON. 1994a pp. 294-295. 

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 ... 

Alternaria has been knovm for centuries to cause various plant diseases such as early blight of potato and various leaf spots and fruit rot. Species of this fungus are widely distributed in soil and on aerial plant parts. Because Alternaria requires high moisture levels (28-34%) for growth, infection of seeds occurs when the seed moisture is high, either in early stages of development or after wetting of crops from rain. 

Safflower seed that is produced in areas with late summer rains or cool weather cycles that interfere with maturation can produce dark-colored or greenish oils that are often higher in FFA as well. If the seed has sprouted before or during harvest or has been attacked by Alternaria, Pseudomonas, or other head-rot diseases, the resulting oil can be quite difficult to refine and extremely difficult to bleach. 

Leaves with yellow-hrown, concentrically ringed spots. Cause Alternaria blight. This t jngal disease attacks lower leaves first. Spots merge and leaves die as the disease progresses. Plants eventually die. Spray plants with copper at the first sign of symptoms. Plant tolerant cultivars such as Hybrid H to prevent problems. 

Fruit with spots flesh may rot. Causes Angular leaf spot Alternaria blight black rot scab other fungal or bacterial diseases. See "Leaves with spots, blotches, or brown areas on page 85 for controls. 

Dark brown spots with concentric rings, usually appearing on older leaves first, are caused by Alternaria leaf blight. As the disease progresses, leaves curl down and eventually drop off. Fruit infected with this disease has brown, concentrically ringed, sunken spots. Prevent problems by planting resistant culti-vars such as Earligold , Pulsar , and Saticoy . 

Leaves with spots, blotches, or brown areas. Causes Powdery mildew angular leaf spot scab Alternaria leaf blight other fungal and bacterial diseases. Various diseases attack squash. Reduce problems by keeping foliage dry when watering and by not touching plants when wet. Spray infected plants with a dilute solution of copper spray to reduce the spread of the disease. 

Alternaria solani, the causal organism of early blight disease of tomato and potato produces several metabolites whose structures have been clarified. It was pointed out that the fungus also secretes host-specific toxins which induce necrotic symptoms typically associated with the disease [50]. Five phytotoxins were isolated, solanapyrones A (67), B (68), C (69), D (70) and E (71), Fig. 17. The diastereomeric... 

HC-Toxin and victorin are produced by Helminthosporium carborum, which is a pathogen on maize, whilst another peptide, AM-toxin, is produced by Alternaria alternata, which causes a blotch disease on apples. The peptabiols, produced by Trichoderma harzianum, affect the development of other fungi. 

Alternaria species are associated with several leaf-spot diseases of plants. Alternaric acid (8.10), produced by A. solani, which is the cause of early blight on potatoes and tomatoes, has a marked phytotoxic activity and may be responsible for many of the symptoms of the plant disease caused by the fungus. It also shows a specific anti-fungal activity. The branched chain structure is biosynthesized from nine acetate units and three Ci units derived from formate. The solanopyrones are another group of phytotoxic metabolites of A. solani. Solanopyrone A (8.11) induced necrotic lesions on the leaves of potatoes typical of this fungal infection. The structures of the solanopyrones were established by... 

Alternaria alternata is an airborne fungus. It causes the so-called brown spot, one of the most destructive leafspot diseases on tobacco, peppers, tomatoes, and other plants. Fungi Alternaria Alternaria species include arouud 50 kuown fungi) are commonly... 

According to the investigations of Fattinger (1950), the fungicidal action of copper is enhanced by cadmium, cobalt, nickel and zinc compounds in Alternaria tenuis and Trichothecium roseum cultures. Zinc sulfate (ZnSO 7HjO) was tried in place of copper sulfate its effect however was inferior to that of the copper compound. Nevertheless, it is still used against rosette disease a physiological disease caused by zinc deficiency. 

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