东北春大豆田蛴螬防治指标研究

为明确全球气候变暖趋势下和国家“双减”方针指导下的东北春大豆田蛴螬防治指标，在沈阳春大豆田播种后采用人工接虫的方法，研究了不同虫口密度下的东北大黑鳃金龟3龄幼虫对大豆死亡株率和大豆产量的影响。结果表明，大豆产量（y）与虫口密度（x）呈负相关关系（y =﹣0.0135x﹢0.4232，32>x≥1，r =﹣0.990），产量损失率（y）与蛴螬虫口密度（x）与间存在线性相关关系（y=3.0051x﹢2.6781，x≥1，r=0.991）；x≥4，即虫口密度≥4，产量与产量损失率均达到显著差异；基于防治收益应大于防治成本的原则，确定了东北春大豆田东北大黑鳃金龟3龄蛴螬幼虫的防治指标应为2.33头/m2。不同时期、不同虫口密度下蛴螬危害造成的大豆死亡株率间存在较大差异。每平方米有1~5头蛴螬为害时，大豆苗期（V1）死亡株率达到48.18%~57.87%，至大豆初花期（R1）大豆死亡株率达到65.67%~75.05%，V1期死亡株率远大于V1至RI阶段的死亡株率，因此要加强苗期蛴螬的防治工作。

Damage of action threshold of Holotrichia diomphalia 3rd instar larvae in spring sowing soybean field in Northeast China

To establish appropriate control index for Holotrichia diomphalia Bates in the context of a continualglobal warming trend and guidelines based on“Dual Reduction”in chemical fertilizers and pesticides, mortalityrates and yield of spring soybean in Northeast China were investigated by artificial inoculation with different densityof Holotrichia diomphalia 3rd instar larvae. The results showed that yield had negative correlation with larvae density(y =﹣0.0135x﹢0.4232，32>x≥1，r =﹣0.990 ), yield loss rate had positive correlation with larvae density (y=3.0051x﹢2.6781，x≥1，r=0.991). The yield and yield loss rate were significantly different when larvae density wasgreater than or equal to 4. According to the rule that the direct benefit was above the cost of control, we determinedthat the damage of action threshold of H. diomphalia 3rd instar larvae was 2.33 heads per square meter in Northeastspring soybean yield. The mortality rates caused by H. diomphalia 3rd instar larvae were significant different with dif⁃ferent population density at different survey periods. The mortality rate ranged from 48.18% to 57.87% at the seed⁃lings stage ( V1 ) when the population density was 1 - 5 heads per square meter, and it ranged from 65.67% to75.05% until the primary flowering stage ( R1 ). The mortality rate in V1 stage was significantly greater than that inV1 to RI stage. Therefore, the control of grubs would be best performed at seedling stage.