释放中华草蛉作为综合防治桔全爪螨的一项措施

实验室观察证明中华草蛉(Chrysopa sinica)幼虫期平均能捕食桔全爪螨(Panonychus citri)1392头,最多2584头。小区试验按1:100—200比例释放初孵幼虫防治桔全爪螨,5天后叶螨虫口下降90.09％;对照区仅下降0.26％。草蛉释放量减少,效果也降低。当释放草蛉的果树上猎物大量减少时,草蛉幼虫就下树迁移。 1979—82年在四川南充等县进行田间试验,证明早春天敌尚未活动前,在桔全爪螨孵化盛期喷洒农药压低基数,4、6、6月挑治点片发生的害虫,5、6月释放草蛉,综合治理能收到良好效果,比单纯化防区节省农药62.5—83.4％,减少生产投资31.25％。从麦田采草蛉茧,室内养成虫获卵释放,是人工利用草蛉最经济有效的办法。

FIELD RELEASE OF CHRYSOPA SINICA AS A STRATEGY IN THE INTEGRATED CONTROL OF PANONYCHUS CITRI

Laboratory observation showed that Chrysopa sinica consumed 1392(maximum 2584) Panonychus citri in its larval stage. When newly hatchedlarvae of C. sinica were released at a ratio of 1 : 100-200 against P. citriin a plot test, the mite population was reduced 90,09% in 5 days comparedto only 0.26% in the check plots.. Reducing the number of C. sinica released decreased the control efficacy. Larvae of Chrysopa usually left the trees and migrated elsewhere when pest population was greatly diminished.Integrated pest control measures for P. citri have been practiced since 1979 in several counties of Sichuan.Spraying in early spring when mites were hatching and natural enemies were not active, and spot treatment of minor insect pests in April-June,gave good results with a saving of insecticide usage of 62.5-83.4% and a reduction in production Cost of 31.25%.Collecting cocoons from wheat fields and releasing the eggs deposited by the emerging adults was found to be the most economieal way to utilize C. Sinica in the control of P. citri.