应用异小杆线虫防治桑天牛的研究

USING ENTOMOPATHOGENIC NEMATODE Heterorhabditis bacteriophora FOR CONTROL OF MULBERRY LONGICORN Apriona germari HOPE

经多年（1992～1995）筛选试验，发现从我国山东土壤诱集的病原线虫Heterorhabditisbacteriophora8406对桑天牛防治效果最佳。在广东地区应用线虫防治桑天牛的最适温度为23±5℃，最佳时间为10～12月份。大田400hm2推广示范结果表明，使用注射量为3×103～4×103条线虫／mL，防治效果达86％～98％。从2年田间应用线虫后桑叶喂蚕的安全性测定表明，与对照相比无显著差异。

Mulberry longicorn Apriona germari Hope is a harmful pest in mulberry orchards and has one generation per year in Guangdong. The damage duration is 7~8 months in a year. Efforts for the control of this pest by conventional methods were not very successful until 1992 when entomopathogenic nematodes were used. After bioassays on the infectivity of 10 strains of entomopathogenic Steinernema and Heterorhabditis nematodes against mulberry longicorns larvae, Heterorhabditis bacteriophora 8406 strain isolated from the soil of apple orchards at Shandong Province was most effective against larvae of the mulberry longicorns. It was demonstrated that the optimum temperature for fleld use of nematodes against this pest was 23±5℃ and the optimum control time was in October - December. Field trial demonstration in an area of about 400 hm2. (6, 000 mu)showed that, with a dosage of 3 × 103~4 × 103/mL nematodes injected, H. bacteriophora 8406 reduced mulberry longicorn larvae, by 86%~98%. The safety tests of nematodesfor the silkworrns showed that appropriate application of nematodeS in the field did not contaminate the leaves of mulberry or affect the quality of the leaves as food for silk worms.