by Cooperative Extension, College of Agriculture and Home Economics, Washington State University in Pullman, [Wash.] .
Written in English
|Series||EB -- 1418., Extension bulletin (Washington State University. Cooperative Extension) -- 1418.|
|The Physical Object|
|Pagination|| p. :|
The temperature range for purple spot is C; however the disease reaches its peak activity from C. Infections during harvest often occur as a result of microscopic wounds caused by wind damage or sand blasting. The stomata also act as a point of entry for this pathogen. Purple spot and Stemphylium leaf spot Purple spot lesions occur mainly on lower half of asparagus spear. Internal tissue is not affected. Stemphylium leaf spot causes large elliptical le- sions on summer fern (left). Lesions have a dark margin and light brown to gray center. Small black spots . A severe purple spot infection (causal agent; Stemphylium vesicarium, teleomorph Pleospora herbarum) early in the growing season can defoliate asparagus ferns prematurely, resulting in decreased yields of susceptible varieties, especially if defoliation occurs in consecutive years. Infection of spears is unsightly and commercially unacceptable. Purple spot on asparagus (Asparagus officinalis) spears and ferns is caused by the fungus Stemphylium vesicarium, and has become a significant problem for asparagus production in Michigan. Rust is another foliar disease and is caused by the fungus Puccinia by: 2.
Asparagus purple spot develops on emerging spears. in spring and occurs ferns in summer destroying. stem, branches, and leaves, which result in reduction. of the flow of carbohydrates . Purple spot of asparagus is a disease of increasing importance in Victoria and Australia. Glyceraldehydephosphate dehydrogenase gene sequences and morphological characters revealed the causal agent to be Stemphylium vesicarium, rather than the often-reported S. botryosum. Implications for disease control are by: 5. Asparagus; evaluation of spray treatments for control of purple spot (Stemphylium vesicarium) Asparagus purple spot: field evaluation of urea application rates and timing, and calcium cyanamide application to enhance crop debris degradation and reduce disease on the emerging new crop. Purple spot caused by the fungus Stemphylium vesicarium is a disease that causes heavy damage in asparagus crops. It infects the leaves and stem and results in degradation of the quality in the harvested asparagus shoots, lowering their commercial by: 5.
Purple spot disease on asparagus spears and fern is caused by the fungus Stemphylium vesicarium. The fungus survives the winter as sexual spores (ascospores) in a sac (ascus) produced in overwintering structures (pseudothecia) that appear as small black dots on asparagus debris from the previous season. The ascospores are released from the. Elaine Roddy, Vegetable Crops Specialist OMAFRA, Ridgetown Purple spot is a significant disease of asparagus. During wet, windy weather conditions, purple spots develop on the emerging spears. These purple spots do not impact either the flavour or texture of the spear. In . In New Zealand purple spot of asparagus spears and leaf spot of asparagus fern are caused by Stemphylium vesicarium (Wallroth) Simmons (teleomorph Pleospora sp.). Ascospores and conidia were both trapped above asparagus crops during the Cited by: S. vesicarium was isolated from c. 80% of small ( mm) elliptical, purplish spots on freshly harvested spears. Alternaria sp. was isolated from c. 20%. The lesions were not associated with any major breakdown of tissue, but made the spears unsightly, rendering them unsuitable for fresh sale or processing. In inoculation tests, S. vesicarium was pathogenic only on wounded tissue; A. was not Cited by: