小卷蛾斯氏线虫对辣椒烟粉虱的控制作用

本文研究了小卷蛾斯氏线虫Steinernema carpocapsae对烟粉虱Bemisia tabaci的侵染能力以及对田间辣椒烟粉虱的控制作用。结果表明，室温（28±2）℃，空气湿度（60±5）%，辣椒叶背面湿润的条件下，线虫约在4 h侵入烟粉虱若虫体内，2～3 d内致其死亡。不同浓度线虫对烟粉虱若虫的控制效果不同，小卷蛾斯氏线虫All品系22、16和13 IJs/mL对烟粉虱高龄（3龄和4龄）若虫的致死率分别为42.79%，34.74%，29.31%，对低龄（1龄和2龄）若虫的致死率分别为44.58%、41.66%、39.61%。助剂5% d-柠檬烯可溶液剂与线虫联合使用具有促进效果，线虫稀释22 IJs/mL，配合1000倍液5% d-柠檬烯可溶液剂时效果最佳，高龄若虫和低龄若虫的致死率分别达到60.61%和61.55%。田间辣椒叶片表面施水量对烟粉虱的防治效果存在明显的影响，在田间施水1.5、1、0.5 L/m²的条件下，高龄若虫校正死亡率分别为66.49%、66.50%、47.78%，低龄若虫校正防治效果分别为69.30%、58.52%、51.83%。综上，喷施小卷蛾斯氏线虫对烟粉虱有一定的控制效果，配合助剂5% d-柠檬烯可溶液剂有促进作用，保持辣椒叶片表面湿润可以提高对烟粉虱的防治效果。

Control of Bemisia tabaci in Pepper by Steinernema carpocapsae

Infection of Bemisia tabaci by Steinernema carpocapsae was evaluated by artificial inoculation and field control efficacy was assessed on pepper plants.Our results showed that the nematodes invaded into the whitefly nymphs in 4 h and caused nymph death in 2—3 d at the conditions of(28±2)℃,humidity of 60%,and humid pepper leaf back.The nematodes showed concentration-dependent control of B.tabaci.The mortalities caused by 22,16,and 13 nematodes/mL of the nematode-containing fluids were 42.79%,34.74%,and 29.31%in elder(third and fourth instar),respectively,and 44.58%,41.66%,and 39.61%in younger(first and second instar)nymphs of B.tabaci,respectively.The combined use of adjuvant 5%d-limonene SL with the nematodes increased the control.The optimal result was observed when 300-fold dilution of nematodes was combined with 1000-fold dilution of the adjuvant,which exhibited the highest mortalities of 60.61%and 61.55%in the elder and younger nymphs,respectively.The control was also significantly affected by the humidity on the leaf surface.When water was sprayed at 1.5 L,1 L,and 0.5 L per square meter in the field,the corrected control were 66.49%,66.50%,and 47.78%for old nymphs,and 69.30%,58.52%,and 51.83%for younger nymphs,respectively.Our results indicate that the nematodes have the potential control B.tabaci,which can be promoted by adding adjuvants and keeping leaf surface humid.