Efficacy of the entomopathogenic nematodes against whiteflies, Bemisia tabaci (Homoptera: Aleyrodidae), in chili peppers under laboratory and field conditions

Abstract

The efficiency of entomopathogenic nematodes against whiteflies, Bemisia tabaci, was studied with the following objectives: 1) to test which life stage of whitefly is most susceptible to entomopathogenic nematodes; 2) to obtain the best entomopathogenic nematode species and surfactants which provide the greatest control of whiteflies. The first results showed that the stage of whitefly most susceptible to nematodes were the third and second instar larval stages with mortality rates of 96.66 and 90%, respectively. The results from using different species of nematode revealed that Steinernema carpocapsae was better at controlling whiteflies than S. feltiae and S. siamkayai with LD50 and LD90 values at 33.4 and 56.5, respectively. After comparing different surfactants which help to promote the use of nematodes on whiteflies, the results showed that the most suitable surfactant was “Super”, causing the highest mortality rate at 86.48±5.78%. The field trial was carried out at Ban Hong Duer, Khon Kaen province. The results from the nematode-treated plot exhibited dramatically decreased number of whiteflies whereas the farmer’s practice plot showed an increasing trend.