![]() Stems can also develop elongated, greyish watery brown lesions. In dry weather, affected foliar parts may appear dry and shrivelled. In moist conditions, a downy white greyish mould usually develops near the margin of leaf spots on the underside of leaves. The spots may enlarge rapidly until entire leaflets are killed. Leaf spot margins often are pale green or water-soaked. On leaves, pale green to brown spots, sometimes with a purplish tinge, appear on the upper surface of leaves. In potatoes, tubers can also be infected. Late blight symptoms can develop on leaves, stems, branches, and in case of tomatoes on both green and ripe fruits. When conditions favour development of late blight and there are no steps taken to suppress the disease, it can completely destroy the above-ground parts of plants (stems, leaves, tomato fruits) and can also affect potato tubers. It is known as the most devastating disease of potatoes. Late blight of potatoes or tomatoes can be devastating with dramatic and disastrous economic consequences. JWash Acad Sci 23: 435–446.Late blight is a fungal disease that can affect many vegetables of the Solanum species, mainly potatoes and tomatoes, but also eggplants. The dark ages in plant pathology in America: 1830–1870. A second world migration (and population displacement) of the potato late blight fungus? Plant Pathol 40: 422–430. Production and germination of oospores of Phytophthora infestans. A Source Book of the Genus Phytophthora infestans. ![]() Assessment of field responses of potato cultivars and breeder seedlings to potato late blight epidemics. Phytophthora infestans: The Mexican connection. The blight, the blighter, and the blighted. An alternative possible origin of the A2 Mating type of Phytophthora infestans outside Mexico. (Ed.) 1981 Compendium of Potato Diseases. Strains of Phytophthora infestans from Switzerland with A2 mating type behavior. Use of detached leaf assay for evaluating late reactions of potato and tomato. An efficient technique for prolonged storage of Phytophthora infestans. Direct detetion of gene flow and probable sexual reproduction of Phytophtora infestans in Northern North America. Migration from northern Mexico as the probable cause of recent genetic changes in populations of Phytophthora infestans in the United States and Canada. Panglobal distribution of a single clonal lineage of the Irish potato famine fungus. Genetic analyses of interspecific hybrids between Phytophthora infestans and Phytophthora mirabilis Exp Mycol 18: 20–32. A second world-wide migration (and population displacement) of the potato late blight fungus? Plant Pathol 40: 422–430. ![]() Population genetic structure of Phytophthora infestans in the Netherlands. Historical and recent migrations of Phytophthora infestans. Occurrence of A2 mating type of Phytophthora infestans in potato fields in the United States and Canada. Early reports of destructive attacks of late blight on tomatoes in England. infestans on detached and intact leaves of potato cultivars Green Mountain and Kennebec and the tomato cultivar Bonnie Best.Īllard, H.A. There were no significant differences in reactions to isolates of P. ![]() Lesion growth was determined 4, 5, and 6 days following inoculation. Leaves on intact tomato and potato plants were inoculated in a similar manner and placed in a mist chamber. The supporting hardware cloth was placed 2.5 cm above distilled water (2.5 cm deep) in 31 cm × 17 cm × 8 cm clear plastic boxes with tight fitting lids. A single disc was placed on the center of the tomato leaf. A 12.5 mm sensi-disc containing 50μl of 2 × 10 4 zoospores was placed in the centers of the terminal leaflet and the second leaflet pair of the potato leaf. ![]() The leaves in the aqua tubes were placed with abaxial sides down on galvanized metal hardware cloth (12.5 × 12.5 mm mesh). Their petioles were inserted into 14 mm × 100 mm floral aqua tubes containing 9 ml of sterilized distilled water. Primary leaves from the third to the sixth node of potato plants, and the fourth to sixth node of tomato plants were excised at the stem. We developed a detached leaf method for evaluating potato ( Solanum tuberosum L.) and tomato ( Lycopersicon esculentum Mill.) germplasm for reactions to Phytophthora infestans, the causal organism of late blight. ![]()
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