Variability in Pathogenicity and Symptomatology of Leptosphaerulina crassiasca on Peanut. P. Subrahmanyam, Visiting Research Scientist, Texas A&M University, Texas Agricultural Experimental Station, P.O. Box 755, Yoakum 77995. D. H. Smith, Professor, Texas A&M University, Texas Agricultural Experimental Station, P.O. Box 755, Yoakum 77995. Plant Dis. 75:1266-1269. Accepted for publication 23 June 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-1266.

Four of 11 isolates of Leptosphaerulina crassiasca obtained from various sources produced discrete, necrotic-type lesions (pepper spots) on peanut (Arachis hypogaea) leaflets. The other isolates also produced necrotic lesions, which enlarged rapidly and coalesced to produce irregular necrotic areas scattered over the entire leaflet (leaf scorch), depending on the environmental conditions. Wedge-shaped necrotic lesions on leaflet tips, which are often observed in the field, were not produced in inoculation tests in the glasshouse. The optimum temperature range for growth of the fungus in culture was 20–30 C. Production of ascocarps on autoclaved peanut leaf disks was abundant at 20 C.