N. Venugopal Rao ¹, A. S. Reddy ², D. D. R. Reddy ³

Affiliations
1 Regional Agricultural Research Station, Lam, Guntur 522 034, IN
2 Regional Agriculture Research Station, IN
3 Department of Entomology, College of Agriculture, IN

Abstract

The glabrous varieties of cotton favoured higher parasite activity on whitefly, recording more than 40 percent parasitisation, while hairy varieties recorded higher number of predatory mites. The integrated management programme involving natural insecticides of plant and animal origin was significantly superior in conserving the parasite and predatory populations compared to the existing (bollworm based) schedule as well 858 schedule involving some new and highly effective insecticides.

Keywords

Parasites, Predators, Bemisla tabaci, Cotton Varieties, Integrated Management Programme.

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N. Venugopal Rao ¹, A. S. Reddy ², K. Tirumala Rao ¹

Affiliations
1 Regional Agricultural Research Station, Lam, Guntur 522 034, IN
2 Regional Agricultural Research Station, Nandyal, IN

Abstract

The nymphal parasitism of whiteny, Bemisia tabaci Gennadius due to Eretmocerus serius, Eretmocerus sp. and an aphelinid reached 27.4 and 40.2 per cent while the predators Brumoides suturalis (F), Verania vincta, Menochilus sexmaculatus, Chrysoperla carnea (Steph.), Amblyseiuss pp. were at a level of 10.8 and 17.1 numbers per 10 leaves during January and November respectively. The incidence of fungal pathogens viz. Aspergillus sp., Paecilomyces sp. and Fusarium sp., of whitefly was high during November month by suppressing adults, nymphs and eggs to the extent of 86.6, 19.0 and 39.8 per cent respectively. In line with pest population, the parasites were also Influenced by the rainfall which showed significant negative correlations (r  =  0.4275 and 0.3971 respectively). The temperatures also showed a significant correlation with the parasitism, predatory population and mortality due to fungal pathogens.

Keywords

Bemisia tabaci, Phytoseiids, Fungal Pathogens, Abiotic Factors.

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N. Venugopal Rao ¹, A. S. Reddy ², D. D. R. Reddy ³

Affiliations
1 Regional Agricultural Research Station, Lam, Guntur 522034, A.P., IN
2 Regional Agricultural Research Station, Nandyal, IN
3 Department of Entomology, College of Agriculturc, Rajendranagar, Hyderabad 500 030, IN

Abstract

In an evaluation of the effects of different insecticides against the natural enemies of whitefly, Bemisia tabaci Genn., cotton crop treated with synthetic pyrethroids recorded 9.7 per cent parasitism due to aphelinid and it was on par with endosulfan. Pyrethroids were highly detrimental to the predators, recording the lowest number of 2 to 4.3 of early and 0.3 to 1.2 late occurring predators per 10 leaves. The insecticides of natural origin showed 15.8 to 18.1 per cent parasitoid activity and maintained 3.4 to 7.9 predators/l0 leaves. Triazophos and deltaphos recorded the lowest parasitism and predation levels, whereas fenpropethrin recorded a higher level (14.8 per cent) of parasitism.

Keywords

Aphelinid Parasitoid, Predators, Bemisia tabaci, Synthetic Pyrethroids, Natural Insecticides.

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