杀虫剂防治水稻褐飞虱的有效利用率分析

通过综合分析杀虫剂对水稻褐飞虱的毒力测定结果、褐飞虱田间防治指标、杀虫剂田间推荐剂量及杀虫剂经稻田叶面喷施后在田间的分布等文献资料，发现杀虫剂防治褐飞虱的田间推荐剂量的有效利用率不足0.1%。理论上，通过室内毒力测定可获得杀虫剂杀死褐飞虱种群90%个体的致死剂量 (LD₉₀，单位:μg/头)，用稻田中褐飞虱的发生量乘以LD₉₀值即为杀死90%田间虫量的杀虫剂有效用量；而实际上杀虫剂的田间推荐剂量却是其有效用量的千倍以上。分析出现这种现象的原因可能有:1) 在褐飞虱为害的水稻孕穗期和扬花期，采用手动喷雾器进行叶面喷雾时，杀虫剂在水稻上的沉积率为34.25%～46.10%，但其中82%以上分布在水稻冠层以上部位，分布在水稻基部茎秆部位的不足2%，只占杀虫剂使用量的0.5%左右；2) 褐飞虱获取致死剂量的杀虫剂后死亡，但杀虫剂和褐飞虱在田间的分布极不均匀，当最低剂量的杀虫剂和最多虫量的褐飞虱出现在同一株水稻上时，该剂量必须能够控制褐飞虱的为害，那么对于有更多杀虫剂和更少褐飞虱的植株而言，就必然造成杀虫剂的浪费，从而降低其有效利用率；3) 约有50%以上的杀虫剂洒落在稻田水中，经田水稀释后的质量浓度远远低于杀死褐飞虱种群10%个体的致死浓度 (LC₁₀值，单位:mg/L)，不能有效杀死褐飞虱。作者认为，通过人工智能，将杀虫剂直接喷洒在褐飞虱发生为害的部位，并根据虫量进行变量施药，必将大幅提高杀虫剂防治水稻褐飞虱的有效利用率。

Analysis of pesticide efficiency of insecticides against brown planthopper, Nilaparvata lugens Stål

According to the reported data, such as the toxicity of pesticide against the brown planthoppe, Nilaparvata lugens St?l, the field distribution of pesticides after leaf spraying and etc., it was found that the effective utilization rate of insecticides for controlling N. lugens was less than 0.1%. LD₉₀ (μg/pest), which was determined by indoor bioassay, was the lethal dose of the insecticides which can kill 90% population of N. lugens. Theoretically, the amount of N. lugens in paddy field multiply by LD₉₀ was the dosage to kill 90% population of the pest. However, the recommended dosage of insecticides was 1000 times higher than the theoretical effective dosage. There were three reasons for this phenomenon. First, during the booting stage and flowering stage of rice, which were the harmful period of N. lugens, the deposition rate of insecticide on rice plant sprayed by manual sprayer was 34.25%-46.10%, of which more than 82% was distributed at the rice canopy and less than 2% at the rice stem stalk below the canopy. Overall, only about 0.5% of the insecticide dosage deposited on the rice stem. Second, the N. lugens was killed after treated by a lethal dose. However, the distribution of insecticide and N. lugens was extremely uneven in paddy field. When the lowest dose of insecticide and the largest number of N. lugens were on the same rice plant, the dose of insecticide should still be enough to control N. lugens. Therefore, the dose of insecticide was wasted when the more insecticide doses was deposited on the location with less brown planthopper. Thus, the effective utilization rate of pesticides was further reduced. Third, more than 50% of pesticide dosage dropped in paddy field water and diluted by the water. The concentration of the pesticide was less than the lethal concentration of the insecticides that can kill 10% population of N. lugens (LC₁₀), which could not effectively control N. lugens. Through artificial intelligence, the insecticide was sprayed directly on the site where the N. lugen was harmful, and the insecticide was applied in variable according to the amount of the insect, which will greatly improve the effective utilization rate of the insecticide in the control of N. lugen.