Effects of profenophos and meem extracts on 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 and 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘢𝘤𝘩𝘢𝘦, egg parasitoids of 𝘛𝘳𝘪𝘤𝘩𝘰𝘱𝘭𝘶𝘴𝘪𝘢 𝘯𝘪

Abstract

Use of 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 and 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘢𝘤𝘩𝘢𝘦 has been proposed to manage 𝘛𝘳𝘪𝘤𝘩𝘰𝘱𝘭𝘶𝘴𝘪𝘢 𝘯𝘪 and other caterpillar species in cabbage through augmentation and release. However, use of insecticide is inevitable due to frequent infestation of pest species. For the successful use of 𝘛. 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 and 𝘛. 𝘢𝘤𝘩𝘢𝘦, it is necessary to understand how these insects respond to the insecticides. Along with this objective, effects of neem extracts (81%) and profenophos (500g/l EC) on parasitoids were examined in the laboratory. The direct effect of insecticides on different growth stages of the parasitoids and the indirect effect or effects of insecticide residues on the parasitoids were studied. Of the parasitoids who survived the insecticide treatments, longevity and sex ratio were examined. Residue effect of the insecticides was evaluated 0, 5, 15 and 25 days after spraying. Insecticides were applied as per label instruction. Profenophos significantly affected all the stages of the parasitoid including egg, larval, pupal and adult stages (F=21899; df=2, 87; p<0.05) of 𝘛. 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 with reference to mortality. Similarly, mortality was significant when egg, larva, pupa and adults of 𝘛. 𝘢𝘤𝘩𝘢𝘦 were treated with profenphos (F=20,636; df=2, 87; p<0.05). Mortalities between neem and control were not significant among the growth stages of both species. Longevity and sex ratio of both 𝘛. 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 and 𝘛. 𝘢𝘤𝘩𝘢𝘦 when treated at different growth stages did not vary significantly between neem extract treatment and control. Effect of treatments on the parasitism percentage of both species differed significantly over the time (F=1327, df=1, 216; p<0.05). Results revealed that profenophos showed strong negative effect on the performance of 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 and 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘢𝘤𝘩𝘢𝘦 than neem extract and 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘤𝘩𝘪𝘭𝘰𝘯𝘪𝘴 is more suitable as a biocontrol agent than 𝘛𝘳𝘪𝘤𝘩𝘰𝘨𝘳𝘢𝘮𝘮𝘢 𝘢𝘤𝘩𝘢𝘦.