A PRELIMINARY STUDY ON DELPHACODES STRIATELLA FALL(?)N IN THE VICINITY OF WUCHANG

Delphacodes striatella Fallen is one of the important rice pests in Hupei. Accordingto our observations made in the vicinity of Wuchang, Delphacodes striatella Fallen has 6--7generations per year. It passes winter in the nymphal stage. In winter its nymphs hidein the weeds along the sides of fields and streams. The adult stage lasts 5--42 days,egg stage, 5--15 days, and nymphal stage, 9--31 days. It takes 20--42.5 days to com-plete one generation. Each female lays 62--259 eggs, depositing them in the tissue ofstalk of the host plants. The adults may be classified into two types, the long wing typeand the short wing type. According to the present study on its life history and behavior, we suggest that thepulling of the Echinochloa crusgalli in rice field is the most economical method for con-trolling this pest. Among the insecticides tested we have found 1/150--300 of 6％ γ-BHC,1/1000--1500 Dipterex and 1/200--300 Endrin (19.5％) would give very successful con-trol.