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笼罩试验表明，小麦扬花期，天敌与麦蚜在１３０－１１８０之间时，蚜变系数为０．９８－６．９，更正减退率为４．８％－８６．９％。与化防比较，减产为２．２－１２．３％，天敌与不同麦蚜的比值（ｘ）同减产百分率（ｙ）之间的直线回归方程为ｙ＝－０．０２１１０２７＋０．０００８９６２ｘ，ｒ＝０．９３＊＊。套穗试验与上述结果趋于一致。分析天敌—麦蚜—产量三者之间关系，结合化防指标等，提出以七星瓢虫成虫食量为标准，天敌与麦蚜在１５７时不需化防。根据麦蚜主要天敌的食量，将该指标转换成天敌控蚜头数
The shrouding test showed that the coefficient of variation of aphids was 0.98-6.9 at the flowering stage, natural enemies and wheat aphids were between 130 and 1180, and the corrected reduction rate was 4.8% -86.9%. Compared with the chemical defense, the yield reduction was 2.2-12.3%. The linear regression equation between the ratio of natural enemies to different wheat aphids (x) and the percent yield (y) was y = -0.0211027 + 0.0008962x, r = 0.93 **. Spike test and the above results tend to be consistent. Analysis of natural enemies - wheat aphid - yield relationship between the three, combined with anti-defensive indicators, etc., proposed seven-star ladybug adult food intake as a standard, natural enemies and wheat aphid at 157 without the need of fortification. According to the main natural enemies of wheat aphid food intake, the index converted into natural enemy control head number