Abstract
BackgroundThe 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.ResultsIn 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.ConclusionsStudies 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.
Highlights
The greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), is a cosmopolitan, polyphagous and a serious pest of vegetables and ornamentals in greenhouse
Relative preference of E. formosa to different nymphal stages of T. vaporariorum The relative preference of E. formosa to different nymphal stages of T. vaporariorum was determined by offering 10 nymphs of each instar on French bean leaves for 24 h in 5 replications
Significant differences were recorded in the parasitism (F= 39.64; df=3, 16; p< 0.001), hostfeeding (F=31.04; df= 3, 16; p< 0.001) and total host killing (F= 16.47; df= 3, 16; p< 0.001) rates of E. formosa to different nymphal instars of T. vaporariorum
Summary
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. The greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), a cosmopolitan polyphagous species is found in greenhouses as a serious pest of vegetables and ornamentals (Singh and Sood 2018). Greenhouse whitefly can complete 13 generations in a year It transmits many viral pathogens and produces honeydew for sooty moulds to grow and reduced crop yield (Kos et al 2009). One of the most popular and important biological control agents for the control of the greenhouse whitefly in protected cultivation is the parasitic wasp, Encarsia formosa Gahan (Hymenoptera: Aphelinidae). The work aimed to study the biology and population growth parameters of E. formosa when parasitising nymphs of T. vaporariorum
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