Bt－4生物农药防治棉铃虫的试验

本文对苏云金芽孢杆菌肯尼亚亚种（Ｂａｃｉｌｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓ—Ｋｅｎ）在晋南棉区生态条件下第三代棉铃虫的防治进行了研究。结果表明：Ｂｔ—４对棉铃虫低龄幼虫有极显著的防治效果，１０００ｍｇ／ｋｇＢｔ—４杀虫率高达９２．３１％．药液在棉花苞叶和蕾、铃间形成一药液富集区，与棉铃虫钻蛀棉花蕾、铃的区域一致，这是取得高效防治效果的一个原因．试验表明，在晋南棉区，运用１０００ｍｇ／ｋｇ浓度的Ｂｔ—４在棉铃虫卵或低龄幼虫盛发期施用能有效地防治棉铃虫的危害。并作为一种高效无公害生物农药，Ｂｔ—４可以在该棉区大面积防治中应用．

THE USE OF BT-4 BIOLOGICAL PRSTICIDE FOR THE PREVENTION AND CONTROL OF BOLLOUM (HELIOTHIS ARMIGERA HUBNER)

Different densities of pesticide Bt-4 (Bacillus thuringiensisken) were tested for the prevention and control of bollworm in the agro-ecologicalconditions of the southern Shanxi province. Results indicate Bt-4 can eliminateyounger bollworms. The mortality rate of bollworms of instar 1-3 treated withabout 1000 μg/kg solution Bt-4 is as high as 92. 31%. There are Bt-4 accumulated areas between boil/but and sepals, which are the same areas where the bollworm bores into the bud/boll. This may contribute to Bt-4's effectiveness. Bt-in 1000 μg/kg density can prevent bollworm occurrence during the peak period of egg-laying and younger bollworm stages. Bt-4 pesticide use should b increased in the whole cotton plantation area of southern Shanxi.