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红铃虫Pectinophora!gossypiella(Saunders)的为害可分为直接取食为害和间接诱发病害。两年来每隔5天左右系统剥查吐絮棉铃,分析结果表明,受害棉籽产量损失平均为60.92克籽棉/千粒,每头幼虫平均为害2.03粒棉籽。根据单铃幼虫数估计的每条幼虫为害造成的产量损失是籽棉0.24克,皮棉0.101克,其中直接为害分别是0.133克和0.0467克,间接为害分别是0.11克和0.0543克。棉籽受害后皮棉等级降低4级,单价降低31.6%。百斤皮棉单价损失是9.383元/条/铃,其中直接为害5.559元/条,间接为害3.824元/条。应用皮棉产量损失0.101克/条和百斤皮棉单价损失9.383元/条/铃,推导了估计产值损失的公式,可以在生长期的不同阶段估计当时红铃虫所造成的产值损失。
The damage caused by Pectinophora! Gossypiella (Saunders) can be divided into direct feeding damage and indirectly induced disease. In the past two years, the cotton boll bolls were dissected on the system every 5 days or so. The results showed that the average yield loss of affected cottonseed was 60.92g seed cotton per thousand grains, and the average number of cottonseed per adult larvae was 2.03. The yield loss due to each larvae estimated to be based on single bell-jar larvae was 0.24 g of seed cotton and 0.101 g of lint, of which 0.133 g and 0.0467 g were directly harmed, with 0.11 g and 0.0543 g for indirect damage respectively. Cottonseed after the damage level reduced 4, the unit price decreased 31.6%. Per unit price of lint cotton loss is 9.383 yuan / piece / bell, of which 5.559 yuan direct damage, 3.824 yuan / indirect damage. Applying the loss of lint yield of 0.101 g / l and the loss of lint weight of pound lint to RMB 9.383 / g / bell, the formula for estimating the loss of output value was deduced. The loss of output value caused by R. brassicae could be estimated at different stages of growing season.