Effects of selective insecticides on host searching and oviposition behavior of Neochrysocharis formosa (Westwood) (Hymenoptera: Eulophidae), a larval parasitoid of the American serpentine leafminer

Effects of application of three insecticides (imidacloprid, pymetrozine and lufenuron) on host searching and oviposition behavior of Neochrysocharis formosa (Westwood), a larval parasitoid of the American serpentine leafminer Liriomyza trifolii (Burgess), were investigated in the laboratory. Female wasps spent more than 89% of their time on a leaf of host-infested kidney bean when introduced into a container containing the leaf treated with each insecticide or distilled water. However, wasps spent more time resting near or away from hosts and less time foraging for hosts on the leaves treated with imidacloprid than the other treated leaves. As a result, they encountered, oviposited and fed on hosts less frequently with imidacloprid treated leaves than any other treated leaves. The numbers of host findings, ovipositor insertions and host feedings were also significantly lower on the leaves treated with lufenuron than the control. These results suggest that imidacloprid and lufenuron reduced wasp host searching efficiency.