Short communication. Repellency and toxicity of oils from different origins on Myzus persicae Sulzer (Homoptera: Aphididae) in pepper

Abstract

Three trials have been carried out to assess the repellency and toxicity of oils of different origins on Myzus persicae in pepper plants: a summer mineral oil, refined oils of soya and rapeseed and a crude fish oil. The results obtained suggest that tested oils, in particular fish oil, are feeding deterrents for apterous aphids. These oils did not cause repellency to alate aphids, since the alates freely chose to settle on either oil treated or untreated plants. Only plants treated with the standard insecticide (Cypermethrin) were not colonized by the alates and their nymphs. On the contrary, direct spray of pepper leaves infested with apterous aphids showed that oils were toxic for the aphids, since 12 h after spraying the mortality rates were equal or above 70% in all cases. By this time, among all the oils, the mineral oil showed the best control efficacy (12 h89% mortality rate, statistically comparable with the standard). However, at 36 h mineral oil mortality rate (90%) was similar to that of fish and rapeseed oils.