油桐尺蠖防治指标的研究

本试验用人工剪叶方法,模拟油桐尺蠖对油桐的为害。结果表明,油桐尺蠖的为害对油桐的生长发育、产量和桐油的品质,均有不同程度的影响。为害程度(x)与产量损失率(y)之间,具有幂函数回归关系y=ax~b,按照Headley的防治指标原理,利用Chiang H C的防治指标计算公式,求得进行化防时,以成年树每株3龄幼虫数及卵块数为标准的防治指标分别为:第1代191.3条和1.06个印块;第2代212.8条和1.18个卵块。人工挖蛹的防治指标舞株蛹置为:第1代2.58个.第2代2.53个。

STUDIES ON ECONOMIC THRESHOLD OF Buzura suppressaria

The method of artificial defoliation was used for simulating the injury of Buzura suppressaria to tung tree. The results indicated that the damage of the insect had an effect on the development and yield of tung tree and the quality of tung oil in varying degrees. The regressive relation betwen the extent of damage (x)and the rate of yield loss (y)was y=ax~b. According to the principle of Headley on economic threshold(ET), using the formula of Chiang, H C. for calculating ET, we obtained that the ET of chemical control for the third instar larva and eggs was 191.9 larvae and 1.07 egg masses per tree(the first generation), 200.9 larvae and 1.12 egg masses per tree (the second generation), and that the ET of artificial pupa-digging control for pupa was 2.58 pupae per tree(the first generation)and 2.53 pupae per tree(the second generation).