Management of sucking pests of brinjal (Solanum melongena L.)

Abstract

An investigation on “Management of sucking pests of brinjal (Solanum melongena L.)” was carried out at College of Agriculture, Vellayani during 2013-2014. The objectives were to assess the intensity of damage caused by sucking pests in brinjal and evolve a suitable management strategy using newer insecticides. Survey conducted in 60 homesteads of vegetable growing tracts of Thiruvananthapuram district revealed the incidence of seven sucking pests namely leaf hopper, Amrasca biguttula biguttula (Ishida), aphid, Aphis gossypii Glover, whitefly, Bemisia tabaci Gennadius, spiralling whitefly, Aleurodicus dispersus, brinjal mealy bug, Coccidohystrix insolita Green, lace wing bug, Urentius hystricellus (Richt) and mite, Tetranychus sp. on brinjal grown in garden land and terrace. The leaf hopper, aphid, whiteflies and mealy bug were the major sucking pests infesting brinjal in the garden land and terrace during the vegetative and flowering stages. The infestation of the leaf hopper was recorded from all the locations surveyed and aphid, whitefly (B. tabacii) and mealy bug in 89.17, 86.67 and 85 per cent homesteads respectively. The damage caused by the pests ranged from 35.35 to 58.88, 30.11 to 40.24, 34.46 to 50.50 and 34.16 to 49.28 per cent by leaf hopper, B. tabacii, aphid and mealy bug respectively. A predator viz., Spalgis epius (Westwood) and a pathogen Fusarium sp. were isolated from the mealy bug, C. insolita. Two field trials conducted to evaluate the efficacy of the new generation insecticides viz., spiromesifen 96 g ai ha-1, thiamethoxam 50 g ai ha-1, acetamiprid 10 g ai ha-1, dinotefuran 30 g ai ha-1, dimethoate 600 g ai ha-1 and biopesticides viz., oxuron 5ml l-1 and Beauveria bassiana 20 g l-1 revealed that the new generation insecticides reduced the population of sucking pests significantly. Thiamethoxam 50 g ai ha-1 resulted in significant reduction in the population of leaf hopper (1.10 plant-1) and was on par with spiromesifen 96 g ai ha-1 (1.12 plant-1) in the first crop. Spiromesifen treated plot recorded highest yield of 10.36 kg plot-1 and it was on par with thiamethoxam (9.56 kg plot-1). Spiromesifen 96 g ai ha-1 reduced the population of whitefly (1.13 plant-1) and it was on par with thiamethoxam 50 g ai ha-1 (1.34 plant-1) in the second crop. Highest yield was also recorded from spiromesifen 96 g ai ha-1 treated plot (10.95 kg plot-1) followed by thiamethoxam 50 g ai ha-1 (9.42 kg plot-1). The results of the study thus indicated that the leaf hopper A. biguttula biguttula and whitefly B.tabaci were the predominant sucking pests infesting brinjal in the homesteads of Thiruvananthapuram district. The new generation insecticides viz., spiromesifen 96 g ai ha-1 and thiamethoxam 50 g ai ha-1 can be used as alternatives to the highly toxic conventional insecticides against the sucking pests, leaf hopper and whitefly.