Alfalfa Seed Chalcid: Nonpreference Resistance in Alfalfa123

Ovipositional and olfactory behavior of Bruchophagus roddi (Gussakovsky) was studied on resistant and susceptible alfalfa clones. Seed pods of the resistant clone were ovipositionally nonpreferred for 8 days (ages 10–18) vs. 2 days (ages 8–10) in the susceptible clone when caged with 2 ♀ /seed. At a density of 1 ♀/seed, 8-, to 10-day-old seed pods of the resistant clone were nonpreferred. An unidentified olfactory attractant, detected in 10-, to 14-day-old seed pods of the susceptible clone, probably mediated orientation to seed pods and initiation of egg laying.