大豆主要食叶害虫为害当量系统与复合防治指标的研究

STUDIES ON THE INJURY EQUIVALENCY SYSTEM AND MIXED ACTION THRESHOLD OF MAIN SOYBEAN LEAF-FEEDING INSECT PESTS

豆天蛾(Clanis bilineata Walker)、银纹夜蛾(Plusia agnata Standinger)、棉铃虫(He-liothis armigera Hubner)和豆灰蝶(Plebejus argus L.)对黄淮流域大豆生产影响较大,防治指标亟待改进。人工模拟剪叶建立了叶损失率与产量损失的函数方程。逐种测定日食量,求取了每种幼虫不同阶段的校正等量系数,建立了为害当量系统。在考虑多维因素的基础上,建立了大豆不同生育期的复合防治指标。田间调查表明,应用该指标能较好解决4种害虫在田间混合发生,虫龄参差不齐,难以确定防治指标的困难,具有较高实用性。

The relationship between leaf damage and yield loss of soybean wasstudied by synthetically cutting off soybean leaf for simulating themixed damage of the main leaf-feeding insect pests,namely,Clanis bili-neata Walker,Plusia agnata Staudinger,Heliothis armigera Hǚbner andPlebejus argus Linnaeus,the functional equations reflecting this rela-tionship in nutritional and reproductive stages of soybean were devel-oped.The corrected injury equivalency coefficients of the larvae of dif-ferent species were determined,the injury equivalency system and mixedaction thresholds in different stages of soybean were then established.The results of field investigations showed that these action thresholdsare desirable for overcoming the difficult of mixed damage caused bylarvae of four species in confused instars.