用苏芸金杆菌制剂和苦楝油防治槟榔红脉穗螟

CONTROL OF TIRATHABA RUFIVENA WALKER ON ARECA CATECHU WITH ARROW BT AND SEED OIL OF MELIA AZEDARCH L.

应用苏芸金杆菌制剂(Bt乳剂)和苦楝油防治槟榔重要害虫红脉穗螟的研究在海南省进行。室内试验结果表明,Bt乳剂对幼虫具有强毒力。毒力与菌液浓度呈正相关。低浓度菌液(800和1600倍液)处理幼虫,中毒幼虫停食或明显降低取食量,生长受到抑制。四天后统计,幼虫取食量分别比对照降低57.24％和56.57％,虫体增重分别比对照降低98.21％和94.21％。五龄幼虫虽死亡率低,但可带毒进入蛹期而致蛹死亡。用5％苦楝油悬浮液处理,幼虫明显拒食,其生长发育受抑制,四天后拒食率为27.15％,虫体增重率比对照降低46.13％,中毒幼虫因饥饿而慢慢死亡。在Bt和苦楝油药液中分别加入微量的氯氰菊酯可明显提高杀虫效果。田间小区试验结果表明,Bt100倍液与3％苦楝油混用或各自加入10ppm氯氰菊酯,虫口减退率均在89％左右。于幼果期在较大面积上采用Bt100倍液加12.5ppm氯氰菊酯液喷雾一次,虫果率比对照降低93.81％。

A series of laboratory and field experiments on controlling Trirathaba rufivena Walker on Areca palm with Bacillus thuringiensis (BT) and seed oil of Melia azedarch L. (SOM) were carried out in Hainan Island in 1986-1987.The results showed that BT emulsion had strong toxicity, the higher concentration, the stronger to the larvae of the pest. Four days after spraying with BT at 1:800 and 1:1600 dilution, the ingestion and weight growth rate of the poisoned larvae decreased by 57.24%, 56.57%, 98.21%, 94.21% than that of the controls respectively. The pupae from 5th instar larvae could still be killed by the residual BT although the mortality of the larvae was low. Four days after spraying the suspension of 5% SOM, the rate of antifeeding and weight growth of the poisoned larvae reduced by 27.15% and 46.13% than that of the controls respectively, and toxic larvae would be devitalized slowly due to starvation. When BT diluted and 3% SOM were mixed together or each combined with 10 ppm Alphanmethrin for spraying in plot trial, the population of the pest decreased by about 89%, BT diluted at 100 times mixed with 12.5ppm Alphanmethrin was sprayed one time in large area during the young fruit period, the rate of damaged fruit reduced by 93.81% than that of the control.