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United States Department of Agriculture

Agricultural Research Service

Title: Occurrence of Phytophthora Infestans on Hairy Nightshade in Maine: Disease Implications of Isolates from Divergent Hosts and Genotypes

item Olanya, Modesto
item D. H., Lambert - UNIV OF MAINE
item A, Plant - UNIV OF MAINE

Submitted to: Northeast Potato Technology Forum Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2005
Publication Date: March 15, 2005
Citation: Olanya, O.M., D. H., L., A, P. 2005. Occurrence of phytophthora infestans on hairy nightshade in maine: disease implications of isolates from divergent hosts and genotypes. Northeast Potato Technology Forum Abstracts. Page 58

Technical Abstract: Occurrence of Phytopthora infestans on hairy nightshade (Solanum sarrachoides) was detected during the 2004 cropping season in Maine. Allozyme, mating type, epidemic components and potential for sexual reproduction of isolates from diverse hosts and genotypes were assessed in laboratory and growth chamber assays. The inoculum contribution of isolates derived from hairy nightshade was evaluated in cross-inoculation studies. Isolates from hairy nightshade and potato were 100/111/122 genotype and A2 mating type based on allozyme analysis. In cross-inoculation studies, when inoculum was derived from hairy nightshade, the infection frequency of potato and nightshade leaves was 67 and 50%, respectively. When the inoculum source was infected potato, the infection frequency was 83 and 63%, respectively. Progress of late blight incited by isolates from hairy nightshade and potato were similar, and ranged from 54 to 87% after 12 days of incubation. Lesion growth on potato incited by divergent genotypes was significantly different at various incubation temperatures (P<.05). The highest disease severity was detected on the 100/111/122 genotype. In-vitro oospore production varied among crosses of isolates from diverse hosts and genotypes, and the percentage of crosses resulting in oospore production ranged from 0 to 67%. These studies suggest that hairy nightshade is a potential source of late blight inoculum, and disease components can be impacted by genotype and host diversity.

Last Modified: 5/5/2015
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