【摘要】 用田间接虫和模拟打孔方法研究莱青虫在秋甘蓝上的防治指标。莱青虫虫量与甘蓝莱产量呈负相关,其线性回归式为Y=22.7757-0.4323M。人工模拟打孔试验与接虫试验结果一致。甘蓝莱的叶面积损失率与产量损失率成正相关,其线性回归式为Y=0.009549+2.095D±2.0561。根据莱青虫的为害与产量损失的关系,结合防治工本费、收益及害虫的种群动态等,秋甘蓝菜上莱青虫的经济阈值为40—46头/百株。 用序贯抽样法确定了秋甘蓝菜上莱青虫防治与否的理论界限方程分别为:d₁=0.4291N+20.44,d₀=0.4291N-20.44。更多还原

【Abstract】 In order to determine the control criterion of cabbage worm (Pieris rapae L,) on autumn cabbage, different amounts of early 3rd instar larvae were imported onto cabbage plants under field condiions. At the same time, leaf-discs of different areas were cut off from cabbage plants to simulate insect damage. A negative correlation between larva numbers and cabbage yields and a positive correlation between the cut-off leaf areas and cabbage yield loss were established. No significant difference was found between the experimental results of larva importation and leaf cutting. The economic threshold of cabbage worm on autumn cabbage was estimated. The upper and lower limits of cabbage worm control criterion were theoretically determined by means of sequential sampling plan.更多还原