印楝素乳油对水稻二化螟作用方式的研究

Study on the Functional Patterns of Azadirachtin to Rice Stem Borer, Chilo suppressalis (Walker)

以不同稀释度的印楝素乳油处理水稻茎秆,探讨其对水稻二化螟的作用方式。结果表明:印楝素0.750、0.500、0.375、0.300和0.250μL·L-1的浓度处理稻茎,对二化螟拒食率分别为70.82%、65.74%、58.64%、36.69%和23.61%。印楝素乳油处理水稻茎秆饲喂3龄幼虫,0.750和0.500μL·L-1的高浓度处理,幼虫分别于6、12d全部死亡;0.375、0.300和0.250μL·L-1的低浓度处理,对其生长发育有明显的抑制作用。印楝素对二化螟成虫具有较强的产卵忌避作用,10μL·L-1的浓度对成虫产卵忌避率达88.6%。室内毒力测定还表明二化螟蚁螟对印楝素乳油比较敏感。

The biological activity of azadirachtin for rice stem borer, Chilo suppressalis (walker) was systematically studied in this paper. The results showed that the antifeedant rates of the newly-hatched larvae reached 70.82%, 65.74%, 58.64%, 36.69% and 23.61% after feeding on paddy treated with 0.750, 0.500, 0.375, 0.300 and (0.250 μL·L^(-1)of) azadirachtin dosages. The 3rd-instar larvae completely died in 6 or 12 days respectively after feeding on paddy treated with 0.750 and 0.500 μL·L^(-1)of azadirachtin dosage. The larvae development was obviously suppressed when treated with 0.375, 0.300 and 0.250 μL·L^(-1)of azadirachtin dosages. Azadirachtin deterred adults from laying eggs on the rice sprayed with azadirachtin. The oviposition deterrence rate reached 88.6% when adults were treated with 10 μL·L^(-1)of azadirachtin. Results of toxity determined in laboratory indicated that newly-hatched larvae were sensitive to azadirachtin.