吡蚜酮对水稻褐飞虱取食行为的影响

吡蚜酮是防治褐飞虱的推荐替代杀虫剂之一。取食选择性试验表明,0.1g/L吡蚜酮处理和清水处理24h稻株上的平均落虫数分别为(1.6±1.2)头/株和(1.5±0.9)头/株。刺探电位技术监测发现,与清水对照相比,0.1g/L吡蚜酮浸苗处理下褐飞虱的口针刺探频次、韧皮部刺入频次、在韧皮部外部活动的持续时间以及木质部取食行为的持续时间没有显著差异,而褐飞虱的非刺探持续时间显著增加,褐飞虱在韧皮部内摄取汁液被极显著干扰,吡蚜酮处理后4h内褐飞虱成虫在韧皮部取食的总持续时间只有(1.2±0.5)min,而在对照上的总持续时间为(65.1±11.3)min。取食恢复试验表明吡蚜酮对褐飞虱韧皮部取食的抑制作用可逆,但是取食抑制的恢复非常缓慢。经吡蚜酮0.1g/L处理24h再转移至清水处理苗上120h后,韧皮部取食的总持续时间也仅约为10min。研究表明,吡蚜酮对褐飞虱没有驱避性和拒食性,不阻碍褐飞虱口针刺探和木质部取食,但对韧皮部取食具有明显的抑制作用,且这种抑制作用恢复非常缓慢。因此,吡蚜酮防治褐飞虱的持效期较长。

Effects of Pymetrozine on the Feeding Behaviour of Rice Brown Planthopper,Nilaparvata lugens (St(a)l)

Pymetrozine is one of the recommended alternatives for controlling rice brown planthopper, Nilaparvata lugens (Stl). Initial feeding choice experiments with winged female adults showed that after 24 h, there were no significant differences between the numbers of planthoppers alighting on untreated rice plants and those treated with 01 g/L pymetrozine (15±09 adults and 16±12 adults, respectively). Electrical penetration graph (EPG) data indicated that after the treatment of 01 g/L pymetrozine, no significant difference occurred on the frequency of stylet probing, the frequency of penetration into phloem, the duration in the extracellular region of phloem, and the duration of xylem ingestion, while the duration of non probing period increased, and the phloem ingestion behaviour was significantly interrupted compared with the treatment of water. The total duration of phloem ingestion of N. lugens adults in 4 h was only 12±05 min on the plants treated with pymetrozine, whereas 651±113 min on the untreated plants. Feeding recovery data suggested that the inhibition of pymetrozine on the phloem ingestion of N. lugens could be recovered, but took long time. The total duration of phloem ingestionof N. lugens was only about 10 min when the insects were first released to the rice seedlings treated by 01 g/L pymetrozine for 24 h, and then survived insects were transferred to the untreated rice seedlings for 120 h. It is revealed that pymetrozine had no deterrent or antifeeding effects on N. lugens, and did not block the stylet probing and the xylem ingestion of N. lugens. However, it significantly inhibited the phloem ingestion of N. lugens, and the recovery of N. lugens from the inhibitive effects was slow. Thus, pymetrozine has a high and persistent efficacy against N. lugens.