密度和磷钾肥配比对棉花盛花期主要害虫和天敌种群的影响

以转Bt基因抗虫棉科棉 1号为试验品种 ,调查了盛花期棉田主要害虫和天敌的种群数量。结果表明 :棉铃虫、棉花卷叶螟和棉叶蝉的百株虫量在低密度条件下较低 ,高密度条件下较高 ;随磷钾肥配比的提高而增加。盲蝽在高密度中配比和低密度高配比条件下发生量较高 ,在高密度低配比和低密度中配比条件下发生量较低。瓢虫和叶蝉的发生基本一致 ,两者具有追随关系 ;寄生蜂和盲蝽的发生也基本一致 ,两者间相关系数达极显著 ,具有明显的追随关系。盛花期棉叶生理活性与主要害虫和天敌种群数量具有密切关系 ,表明棉株营养是影响转Bt基因抗虫棉田害虫和天敌发生的重要因素 ,对棉田害虫进行综合防治必须考虑到棉花的种植密度和肥料运筹。

Effect of Planting Density and Ratio of Phosphorus to Potassium on the Population of Major Pests and Natural Enemies

With Bt transgenic cotton--Kemian No.1 as the tested material, the effect of planting density and the ratio of phosphorus to potassium on the population of major pests and natural enemies was investigated. The number of Helicoverpa armigera,Sylepta derogata, Empoasca biguttula per 100 plants in lowplantingdensity field was greater than that in highplantingdensity field in full blossom period of cotton.High ratio of phosphorus to potassium significantly increased the number of Helicoverpa armigera,Sylepta derogata, Empoasca biguttula per 100 plants. The incidence of Empoasca biguttula and Ladybird beetle was positively related, while the incidence of Lygus lucorum,Adelphococoris suturalis was significantly positively related. The physiological activities of cotton leaf in full blossom period had a positive effect on the population of pests and natural enemies. Cultural practices including planting density and fertilizer application must be taken into consideration when the pest control strategy was decided.