大豆田二代棉铃虫发生为害规律及其防治

Study on the occurrence and control of the second generation of cotton bollworn in soybean field

198 6～ 1998年调查结果表明 ,第二代棉铃虫 (HeliothisarmigeraHiibner)是危害大豆最严重的世代 ,95 %左右的卵产在大豆中上部的嫩梢、嫩叶、幼荚、花萼和茎基上 ,平均每株落卵 4 .1粒。在大豆上的卵量(Y1)和幼虫量 (Y2 )与第一代蛾量 (x)密切相关 ,其关系式为 :Y1=- 315 .9+1.7783x (n =6 ,r =0 .85 6 2 ) ,Y2 =31.3+0 .134x (n =6 ,r=0 .86 5 2 )。在第二代棉铃虫产卵初盛期应用B .t菌剂 (含孢子 10 0亿个 /ml) 2 0 0倍液喷雾 3次 ,或用 1.8%齐螨素乳油 6 75ml/hm2 ,兑水 810kg喷雾 2次 。

A investigation from 1986～1998 showed that the second generation of cotton bollworn was the most serious insect which infected soybean. 95 percent eggs were laid on the growing top, younger leaves and pod, and the basal stem. There were 4.1 eggs in each plant. The relationship between the amount of eggs (Y 1), the first generation larvae (Y 2) and the first generation moths (x) could be described as Y 1= -315.9 +1.7783x (n=6,r=0.8562 *); Y 2=31.3+0.134x (n=6,r=0.8652 *). A good result have received by using Bt (contain 10 billion spores/ml) soluted 200 times spraying 3 times or 1.8 percent Avermection Ec 675ml/hm 2 with 810kg water sparying 2 times in the early and busy stage of laying eggs.