Influence of some plant extracts and commercial insecticides on the eggs of Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae)

Abstract

Trialeurodes vaporariorum is a serious economic pest of agronomic and ornamental crops. In this study, the methanolic plant extracts (at 80 mg mL⁻¹) of Melia azedarach L. and Peganum harmala L. commercial insecticides (at the maximum label-recommended rate) were individually sprayed on the cucumber plants with the whitefly eggs (6–7 days old) in greenhouse conditions. The control plants were treated with distilled water. During two periods, the numbers of unhatched eggs and emerged nymphs were recorded. The mean numbers of unhatched eggs per leaf were the most in the extract of M. azedarach (9.54) and P. harmala (9.57) as compared with chemical treatments in the last records. Indeed, the plant extracts and insecticides tested proved to be effective on the percentage by which nymph’s population in the first and second records are reduced. During the last record, abamectin and acetamiprid have significantly affected the percentage by which nymph’s population of T. vaporariorum are reduced, followed by the plant extract of M. azedarach, neem oil and P. harmala. These chemicals appear be a potentially safe insecticide in an environment for controlling this pest in integrated pest management programmes.

Keywords:

• greenhouse whiteflies
• plant extracts
• conventional insecticides
• nymphal population

Acknowledgements

The authors would like to thank Hadi Zohdi at Agriculture Research and Natural Resource Center of Kerman, Iran for his help and support.