Effects of Temperature on Pathogenicity and Population Development of Two Isolates of Heterodera lespedezae.

Population development of isolates of Heterodera lespedezae from Illinois and North Carolina was compared on Korean, sericea, and striate lespedezas and red clover at soil temperatures of 14, 18, 22, 26, 30, 34 C (+/- 1 C) and in a greenhouse where temperatures ranged from 19 to 40 C (av. 25 C). Cyst production on all plants, but not at all temperatures, was significantly different between the two isolates. Males of the Illinois isolate were recovered from red clover and striate lespedeza at 22 and 26 C and at greenhouse temperatures. No males of the North Carolina isolate were found on any host. Both isolates retarded growth of striate lespedeza but had no effect on growth of the other species tested.