When jumping on the dorsum of the host, the parasitoid wasp immediately thrusts her ovipositor into the host. This preovipositional stinging which usually lasts 10-100sec has two objectives, i.e., 1) to paralyse the host temporarily during ovipostion, 2) to arrest host molting or pupation after a period of feeding.
Susceptibilities to five chemicals on two different strains of Phytoseiulus persimilis were compared. One was introduced from University of California, Riverside (UCR, susceptible), the other from “Biologische Bundesanstalt für Land- und Forstwirtschaft, Institut für biologische Schädlingsbekampfung” Darmstadt, Federal Republic of Germany, in 1984 through the kindness of Dr. Sherif A. HASSAN (DAS, resistant). Susceptibilities to fenitrothion, carbaryl and chinomethionat were low in the DSA strain. However, susceptibility to acephate was the same and that to permethrin was very high in both strains.
Many leaves of rice plant floated on water in paddy fields early in June. This damage was observed in both direct sowing and transplanting fields. The damage was ascribed to feeding of chironomid larvae, because many larvae were found in the water and on the floated leaves, and a similar damage was recognized by releasing the larvae on rice seedlings. Cricotopus trifasciatus was the main species.