【摘要】 80年代以来,河南棉区红铃虫为害呈加重趋势。据1985—1989年田间试验,早发棉田一代红铃虫平均虫花率1.21%—4.4%,一般棉田为0.6%—2.0%,尚勿须防治;二、三代时,百铃累计卵量每增加100粒,铃害率分别增加7.5%和9.3%,籽棉产量损失分别为0.795%和1.497%。根据防治工本、产量水平和产品价格,估算了经济允许为害水平,计算了亩产皮棉50、75和100kg 棉田的防治指标:按百铃累计卵量取样,二代分别为150、100和76粒,三代分别为94、63和46粒,并经大田生产验证,可以排除由于虫害,品质下降造成的损失,取得了明显的经济和生态效益。更多还原

【Abstract】 In 1985-1989,field experiments were conducted in cotton fields inNanyang and Yucheng Counties,Henan Province for determining theyield losses caused by pink bollworm Pectinophora gossypiella Saunders.The results indicated that the yield damage of 1st generation larvaewas insignificant.The results of linear regression analyses showed thatthe 100 increment of accumulated egg number of 2nd and 3rd genera-tions per hundred bolls caused 7.5% and 9.3% of damaged boll rates,and0.795% and 1.497% of yield loss rates of unginned cotton,respectively.The economic thresholds at low,medium,and high cotton yield levelswere developed as 150,100,and 76 eggs/hundred bolls for 2nd genera-tion,and 94,63,and 46 eggs/hundred bolls for 3rd generation,respec-tively.更多还原