Bionomics and control of Leucoptera scitella in chestnut trees

Leucoptera scitella is a major pest attacking chestnut trees.It has 4 generations a year in Shaoxing and overwinters in stem bark crevices and branches as pupa in cocoon.The overwintering adult emerges and lays eggs in mid April the next year.The larvae of the 1st,2nd ,3rd and 4th generations hatch in the last ten days of April,early June ,mid July and mid August respectively and pupate in mid May,the last ten days of June,early August and the last ten days of September.The adults of the 1st,2nd and 3rd generations emerge and lay eggs in the last ten days of May,early July and early August.Spraying of 1.8%Avermectin EC 1 000 times,5% imidacriplod EC 1 000 times and Shenlu Bt WP 800 times in the larval stage of the first generation can kill 97.2%,98.0% and 85.7% of the pest 5 days after the application.