SEASONAL ABUNDANCE AND MANAGEMENT OF SUCKING PESTS INFESTING OKRA.
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Date
2019-07
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CSKHPKV, Palampur
Abstract
The present investigations entitled “Seasonal abundance and management of sucking pests infesting okra” were undertaken at Experimental Farm of Department of Entomology, CSK HPKV, Palampur during kharif 2018 and farmer’s field at Samloti. The activity of two sucking pests viz., Aphis gossypii and Amrasca biguttula biguttula on okra at Palampur initiated during second and third week of July, respectively and the pests remained associated with the crop till harvest i.e. third week of October. The peak populations of A. gossypii (101.3 aphids/plant) and A. biguttula biguttula (7.2 jassids/plant) were observed during second week of October and fourth week of August, respectively. Whereas, at Samloti the population of A. gossypii, A. biguttula biguttula and Tetranychus urticae started appearing during first week of June and the peak population of 64.4 aphids per plant was recorded during third week of September. The maximum number of jassids per plant (18.6) was observed during last week of August and T. urticae remained on okra crop for a short period having peak population of 11.2 mites per plant during second week of June. Analysis of correlation between weather factors and population of sucking pests on okra at Palampur showed that population of A. gossypii had a significant negative correlation with minimum temperature (r = - 0.6545) and relative humidity (r = - 0.7646). Jassid population showed non-significant relationship with weather parameters. At Samloti, maximum temperature had significant negative effect on A. gossypii (r = - 0.6040) and A. biguttula biguttula (r = - 0.5144). T. urticae showed non-significant positive correlation with maximum and minimum temperature whereas it was negative with relative humidity and rainfall. Efficacy of seven insecticides buprofezin (0.04%), chlorantraniliprole (0.005%) fenazaquin (0.025%), imidacloprid (0.004%), spiromesifen (0.02%), thiamethoxam (0.05%) and cypermethrin (0.014%) was tested against sucking pests infesting okra. The results revealed that imidacloprid (0.004%) was found to be most effective treatment against A. gossypii and A. biguttula biguttula amongst all the insecticides followed by thiamethoxam (0.05%). For the remaining treatments, the decreasing order of efficacy based on the per cent reduction in aphid population was buprofezin, chlorantraniliprole, cypermethrin, fenazaquin and spriromesifen whereas in case of jassids the decreasing order of efficacy was cypermethrin, buprofezin, chlorantraniliprole, spiromesifen and fenazaquin. Imidacloprid treated plots resulted in highest fruit yield and incremental cost benefit ratio followed by thiamethoxam, buprofezin, chlorantraniliprole, cypermethrin, spiromesifen and fenazaquin. In the second trial, one biopesticide and five natural products were evaluated against sucking pests (aphids, jassids). The lowest population of aphids and jassids was recorded in azadirachtin followed by darekastra, rendering azadirachtin and darekastra to be efficacious against these pests.
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