棉铃虫在不同寄主作物上的分布调查

Distribution investigation of Helicoverpa armigera on different host crops

1997～ 1999年在山东省南北 2个主要棉区的巨野和夏津县进行棉铃虫在不同寄主作物上的分布调查。 3年 2地调查结果平均 ,1代棉铃虫卵在小麦上占 93 48% ;2代棉铃虫卵在棉田占 74 13 % ,在春播花生、大豆上占 2 2 78% ;3代棉铃虫卵在棉花上占 72 6 7% ,在大豆上占 10 38% ,在玉米上占 9 38% ,在花生上占 5 17% ;4代棉铃虫卵在棉花上占 6 1 5 9% ,在玉米上占 32 0 2 %。棉铃虫幼虫在不同作物上的分布率与卵有所不同 ,1代幼虫仍然集中在小麦上 ,2、3、4代幼虫在棉花上的分布率减少 ,在花生、大豆、玉米上的分布明显增加。在对棉铃虫采取防治措施的情况下 ,棉花上的各代幼虫分布量进一步减少 ,4代幼虫分布量在棉田只占 2 1 96 % ,而在夏玉米上高达 5 2 5 6 %。特别是 1999年推广普及转Bt基因抗虫棉后 ,在棉花上的幼虫量仅占 9 5 2 % ,夏玉米上增加到 6 3 8%。

From 1997 to 1999, the distribution investigation of cotton bollworm ( Helicoverpa armigera) on different host crops has been conducted in the counties of Juye and Xiajin, which represent the south and north main cotton planting districts of Shandong respectively The average results were that: 93 48% eggs of the first generation were on wheat; eggs for the second generation, 74 13% on cotton and 22 78% on peanut and soybean; as for the third generation, 72 67% on cotton, 10 38% on soyean, 9 38% on maize, 5 17% on peanut; as for the fourth generation, 61 59% on cotton and 32 02% on maize The larva distribution ratios were different from that of the eggs on different crops The larva of the first generation still concentrated on wheat The larva distribution ratios of the second, third and fourth generation on cotton were reduced, while that on peanut, soybean and maize were apparently increased Under the conditions of controlling cotton bollworm, the larva distribution ratios of all generations on cotton were further reduced Of the fourth generation on cotton, the ratio was only 21 96%, whereas on maize, it was 52 56% Especially in 1999 when transgenic Bt cotton was popularized, the larvae quantity of the fourth generation on cotton only accounted for 9 52%, while that on maize increased to 63 8%