Relative preference and demographic parameters of Encarsia formosa Gahan against Trialeurodes vaporariorum (Westwood)

Abstract

Abstract Background The greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), is a cosmopolitan, polyphagous and a serious pest of vegetables and ornamentals in greenhouse. Encarsia formosa Gahan (Hymenoptera: Aphelinidae) is an important primary endoparasitoid species of the greenhouse whitefly. Results In the present study, per cent parasitisation attained 50% on the 4th instar and 46% on the third 3rd instar of T. vaporariorum by E. formosa. The mean duration period of the parasitoid from egg to host mummification, mummification to adult emergence (pupal period) was 11 and 7.8 days on 3rd instar and 8.5 and 7.6 days on 4th instar, respectively. The total time period from egg to adult emergence reached 18.8 days on 3rd instar and 16.2 days on 4th instar. Longevity of the female parasitoids was 8.3 and 8.8 days on 3rd and 4th instars, respectively. The pre-ovipositional, ovipositional and post-ovipositional periods of the parasitoid were 1.2, 6.4 and 1.0 days on 3rd instar and 1.2, 6.7 and 1.0 days on 4th instar, respectively. The finite rate of natural increase (λ), doubling time and weekly multiplication rate of the 3rd instar was 1.16±0.002 times per day, 4.71±0.04 days and 2.80±0.03 folds, respectively and 1.17±0.002 times per day, 4.34±0.04 days and 3.06±0.03 folds for the 4th instar. Conclusions Studies indicated that the 4th nymphal instar of the host was more suitable for parasitisation with E. formosa. The parasitoid species could be mass multiplied and utilised as a component of integrated pest management programme of T. vaporariorum after evaluation under field conditions.

Keywords

• Trialeurodes vaporariorum
• Encarsia formosa
• Biology
• Relative preference