VIEW ARTICLE

Temperature Effects on Curly Top Resistance in Phaseolus vulgaris. M. J. Silbernagel, Research Plant Pathologist, ARS, USDA, Western Region, Irrigated Agriculture Research and Extension Center, Prosser, Washington 99350; A. M. Jafri, Research Plant Pathologist, ARS, USDA, Western Region, Irrigated Agriculture Research and Extension Center, Prosser, Washington 99350, Present address: Department of Plant Pathology, Washington State University, Pullman 99163. Phytopathology 64:825-827. Accepted for publication 4 January 1974. DOI: 10.1094/Phyto-64-825.

Greenhouse and growth-chamber studies indicate that resistance to curly top virus (CTV) in certain snap bean (Phaseolus vulgaris) cultivars may break down at high temp, but is not influenced by the stage of plant development at time of inoculation. The virus was not recovered from inoculated symptomless plants. Plants of the resistant variety in which resistance was broken showed considerable tolerance, since symptoms do not become as severe as on a susceptible variety. In a susceptible variety, higher incubation-period temp increased % CTV incidence and symptom severity and reduced the number of days from inoculation to symptom expression.