白跗平腹小蜂的生物学特性及其利用

BIONOMICS OF PSEUD ANASTATUS ALBIT ARSIS ASHMEAD AND ITS UTILIZATION FOR CONTROL OF DENDROLIMUS PUNCTATUS WALKER

白跗平腹小蜂Pseudanastatus albitarsis Ashmead是多种林业害虫的卵期寄生蜂。在湖南(长沙)每年9月底或10月上中旬产下的卵发育至老熟幼虫期休眠越冬,翌年4月中下旬自然羽化。年发生7—8个世代。在25℃恒温条件下,一世代21—22天,其中卵期2—2.5天,幼虫期6—7天,预蛹期3—4天,蛹期10—11天。有效积温305.64日度,发育起点温度11.55℃。成蜂在常温下不喂食时存活4—5天,喂以蜜糖水寿命可提高7.26倍,每一雌蜂一生平均产卵量246.4粒,日平均产卵量12.4—19.5粒,大部分卵在20天以前产出。温度在20—25℃,湿度60—80％为白跗平腹小蜂适宜繁殖条件。室内可用柞蚕卵大量繁殖。应用白跗平腹小蜂防治第一代马尾松毛虫,实际防治效果达52.30—68.67％,即使高温干燥的夏季用于防治第二代松毛虫,实际防治效果仍达45％左右。是一种有利用前途的天敌。

Pseudanastatus albitarsis Ashmead is an important egg parasite of forest insect pests in Hunan Province and this paper reports its bionomics and utilization for the control of Den,-drolimus punctatus Walker. It breeds 7 to 8 generations each year in Hunan and at 25℃.its life cycle is completed in 21 to 22 days, with egg stage lasting 2 to 2.5 days, larval stage 6 to 7 days, prepupal stage 3 to 4 days and pupal stag: 10 to 11 days. The thermal sum for development is about 305.64 degree days and the thermal threshold of development is 11.6℃. The longevity of the female adults without food is 4 to 5 days and they will live more than 30.days when fed with honey. The total number of eggs produced by each female is 246.4 on average. Oviposition is concentrated within the first 20 days after adult emergence, 12 to 20 eggs are laid each day and the suitable temperature and humidity for oviposition are 20-25℃ and 60-80% R.H. respectively. The fresh eggs and eggs cold stored even for one year of Anthe-rata pernyi Guerin-Menville are good factitious host eggs for mass propagation of the parasite. In field tests for controlling Dendrolimus punciaitis Walker of first and second generation the rates of parasitization were 52.3-68.7% and about 45% respectively by releasing 3000 parasites per mu.