Studies on toxic effects of some plant oils against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and its some important natural enemies

Whiteflies cause economic damage especially in greenhouse cultivation. In this study, the effects of 5 different vegetable oils against the pre-adult stages of whitefly and some of its important natural enemies were investigated. In the experiment, 0.125, 0.25 and 0.5 ml doses of each oil were used, deaths were recorded at the 1st, 3rd, 24th, 48th, and 72nd hours after the application of the oils, and the study was carried out in triplicate. According to the results of the experiment, the species most affected by vegetable oils were predators, pre-adults and parasitoid pupae of whiteflies, respectively. Mortality rates were observed to increase with increasing exposure time to high doses of oils for all insect species. Among the periods of Bemisia tabaci, the periods most affected by fats were the egg, nymph and pupa periods, respectively. At the end of the 72nd hour, it was determined that horse chestnut and cocoa oils affected the egg stages of whitefly to a high degree with 100% mortality rate, while other doses had a moderate and mild effect. It was understood that the individuals most affected by the oils in the trial were the predatory adults, with a high degree of response to borage and horse chestnut oils in the first hours after the administration of the oils. At the end of the 48th hour after the application, it was determined that all Nesidiocoris tenuis and Macrolophus pygmaeus adults died. Again, at the end of the 48th hour, it was determined that all Orius laevigatus adults died in all oils except cocoa butter, and at the end of the 72nd hour, it was moderately affected with a mortality rate of 96.67% in cocoa butter. Parasitoid pupae were found to be the least affected individuals in the trial. However, after 72 hours of exposure to oils, Encarsia formasa was found to be mildly effective in borage oil with a mortality rate of 73.33%, and mildly effective and ineffective in other oils. Eretmocerus eremicus, on the other hand, was the least active against oils in the trial and showed a mild effect, with a 60% mortality rate after 72 hours of exposure to borage oil. As a result, it was understood that while horse chestnut and cocoa oils were highly effective in the pre-adult stages of whiteflies, they had a mild effect on both parasitoid species but had negative effects on predators. Accordingly, it is thought that these oils can be recommended in integrated control programs of whiteflies and used with parasitoid species.