Effect of intercropping on the parasitoids, Encarsia spp. and Trichogramma spp. in cotton fields, India

Intercropping in cotton is of great significance, which helps to reduce the population of insect pests by attracting natural enemies to the field and helping to get stabilized yield and high profit advantage. The study was conducted with 4 intercrops, viz., sesame, Sesamum indicum L.; pigeonpea, Cajanus cajan L.; pearl millet, Pennisetum glaucum L.; and sorghum, Sorghum bicolor L. in an experimental area during 2016 and 2017 autumn season. The objective was to study the population of parasitoids influenced by the intercrops in cotton. This is a triangular relationship between the host, parasitoids, and environment. As Encarsia spp. (Hymenoptera: Aphelinidae) and Trichogramma spp. (Hymenoptera: Trichogrammatidae) are the main parasitoids of insect pests of cotton, thus the study was undertaken on these parasitoids. The results revealed that the highest parasitization of whitefly, Bemisia tabaci (Gennadius) pupae by Encarsia spp., was recorded in cotton-pigeonpea 1:1 (33.22%), which was at par with cotton-pigeonpea 2:1 (32.16%), whereas the second highest one was in cotton-sesame 1:1 (27.33%), while the lowest parasitization was recorded in the control (16.16%). On the activity of Trichogramma spp., the significant highest percent was recorded in cotton-sesame 1:1 (10.93%), while no activity was recorded in cotton-pigeonpea, cotton-sorghum, cotton-pearl millet, and control treatments.