湖南棉田害虫捕食性天敌发生规律及保护利用研究初报

湖南省棉田害虫捕食性天敌昆虫、蜘蛛多达24科80种以上。瓢虫和蜘蛛类占捕食性天敌总量的85%,对棉铃虫种群有重要控制作用。试验表明,棉田实行免耕栽培法,前作茎秆留存,因地制宜开展棉花与大豆、西瓜、玉米、甜叶菊、无架豆角等作物间套作,改进用药模式,选用生物农药和对害虫高效、对天敌杀伤力小的农药品种及安全的施药技术,能有效保护天敌。

Preliminary report of the incidence, preservation and utilization of predatoryinsects and spiders in cotton field in Hunan province

There are 80 species belonging to 24 families predatory insects and spiders in cotton field in Hunan province. Ladybeetles and spiders are the predorminate predators and make up 85% of the total predators. The predators outbreak twice in one year. One Lycosa spp can predate lower instar of cotton boll worm larvae at the rate of 0.19 larvae/24hrs. One ladybeetle nymph can eat eggs of cotton boll worm at the rate of 26.8 eggs/1 day, eat cotton boll worm larvae in the first to the second age at the rate of 8.6 larvae/1 day. When the ratio of pests and predators is within the certain range, It is no need to use pesticide. There are some strategies to protect the predators such as tillage free cultivation, putting up the stem of the previous crop between the cotton line, growing together with other crops such as soybean, watermelon, maize, chrysanthemum and asparagus bean. High efficient bio pesticides and pesticides with low toxic to predators were screened, and safe applications of chemical control were developed.