褐稻虱取食试验及防治探讨

本文用茚三酮法, 以褐稻虱Nilaparvata lugens(stal)排泄的蜜露面积来测定其相对取食量.试验表明:取食量随虫期增大, 逐日取食分布各虫期呈现明显的峰期(图3);发育历期与累积取食量成幂函数关系: N(t)=0.0531t^2.298式中N(t)=累积取食量, t=发育历期(天);褐稻虱各虫期取食率的变化;若以一龄若虫为1计算, 一一四龄若虫取食量比分别为1:1.66:2.10:3.16:10.26, 成虫为73.19;羽化后8天, 短翅型雌虫日均取食量比长翅型雄虫大6.33倍;按褐稻虱的取食行为, 化学防治适期以世代成虫初见期为宜.

ASSESSMENT OF FEEDING OF THE BROWN PLANTHOPPER IN RELATION TO PEST CONTROL

The brown planthopper (BPH) Nilaparvata lugens Stal is a key pest to rice crop in China. Assessment of its feeding has been carried out by means of measuring the areas of honeydew drops on filter paper after treatment with ninhydrin (Heinrichs et al. 1981). The results are as follows.1. The increase of ingestion during the whole life span from egg hatching to adult death is shown in Fig. 3.2. The relation between the developmental stage xpressed in days after hatching and the accumulative quantity of food intake isN(t) = 0.0531t2.298 where, W(t)= the accumulative quantity of food intake; t= days after hatching.3. The ratios of food intake in the durations of different nymphal instars and adult caa be expressed as 1.00, 1.66, 2.10, 3.16, and 10.26 for nymph and 73.17 for adult.4. The averaged food intake of brachypterous females is 6.33-fold over that of macropte-rous males during the first eight days after hatching.5. Based on the assessment of feeding of BPH during its whole life, the suitable dme of carrying out chemical control seems to be the teneral adult stage