Effects of several pesticides on controlling Laodelphax striatellus and Cnaphalocrocis medinalis and killing spiders.

Field experiments with several pesticides were carried out in order to control Laodelphax striatellus and Cnaphalocrocis medinalis and kill spiders.The results indicated that 25%pymetrozine WP(75 g/hm~2)had the best control effect on L.striatellus and the longest duration,and its corrected control efficiency was 80.2%and 90.8%respectively at 3 and 7 days after application.The control efficiencies of 20%chlorantraniliprole SC(30 g/hm~2),25%chlorpyrifos·monosultap WP(375 g/hm2), 15%indoxacarb EC(27 g/hm~2),and 25%avermectin·chlorpyrifos EC(375 g/hm~2) on C.medinalis were all above 80%at 10 days after application,and there were not significant differences between them.Application of 25%pymetrozine WP(75 g/hm~2),15%indoxacarb EC(27 g/hm~2),20%chlorantraniliprole SC(30 g/hm~2)or 25%buprofezin WP(300 g/hm~2)had a rather low killing efficiency on spiders, with the corrected mortality of spiders being 12.6%～28.0%.Application of 5%fipronil SC (30 g/hm~2),48%chlorpyrifos EC(432 g/hm~2)or 2%avermectin EC(13.5 g/hm~2)could reach a rather high control effect on spiders,with the corrected mortality of spiders being up to 90.8%.The field survey showed that compared with blank control,chemical control made the spider population decrease by 51.72%.