SEASONAL OCCURRENCE OF MAJOR INSECT PESTS OF GROUNDNUT AND THEIR MANAGEMENT
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Date
2019
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Acharya N G Ranga Agricultural University, Guntur
Abstract
The present investigation on “Seasonal occurrence of major insect pests of groundnut and their management” was carried out in the Agricultural College Farm, Bapatla during kharif, 2018-19 with an aim to know the seasonal occurrence of pests of groundnut and to know the efficacy of newer insecticides against insect pests and their influence on natural enemies. Seasonal occurrence of thrips and leafhoppers initiated during 36th SMW with a population of 0.97 leafhoppers/plant and 1.14 thrips/plant respectively. The population of leafhoppers reached its peak population of 7.12 leafhoppers/plant during 38th SMW. The population of aphids noticed during 40th SMW and reached its peak during 41st SMW with a population of 1.8 and 4.33 aphids/plant respectively. Larvae of leaf miner and S. litura recorded during 36th SMW with a population of 0.74 and 0.12 larvae/plant respectively with 10.26 and 8.79 per cent leaf damage respectively. Whereas, the peak population of leaf miner and S. litura noticed during 41st SMW with a population of 3.12 and 2.06 larvae/plant respectively with leaf damage of 34.46 and 40.10 per cent respectively. Semilooper population recorded during 36th SMW with a population of 0.72 larvae/plant and the population attained its peak during 37th SMW with 3.36 larvae/plant. Population of bud borer recorded during 40th SMW and highest population during 41st SMW with a population of 0.48 and 2.33 larvae per plant respectively. M. vitrata population observed only during 45th SMW with a population of 1.64 larvae/plant and 15.05 per cent leaf damage. Population of coccinellids and spiders recorded during 36th SMW with a population of 0.18 and 0.32 per plant respectively, and attained their peak population during 41st SMW with a population of 2.01 and 1.12 per plant respectively.
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Among the surveyed mandals of Guntur district, highest leaf miner larval incidence of 0.88 larvae per plant with 24.6 per cent damage during vegetative stage at Karlapalem. Highest number of coccinellids and spiders with 0.20 and 0.92 respectively per plant observed at Bapatla and Cherukupalli mandals respectively. During pegging stage, highest leaf miner larval incidence recorded at Karlapalem with a population of 2.37 larvae per plant with 40.27 per cent leaf damage. Highest number of coccinellids and spiders with a population of 0.45 and 1.64 respectively per plant observed at Pedakakani and Cherukupalli mandals respectively.
In Prakasam district, highest leaf miner larval incidence of 1.2 larvae per plant with 36.25 per cent damage during vegetative stage observed at Chinaganjam. Highest number of coccinellids and spiders observed at Vetapalem with a population of 0.44 and 0.68 respectively per plant. During pegging stage, highest larval incidence recorded of 2.59 larvae per plant with 43.21 per cent leaf damage observed at Chinaganjam. Highest number of coccinellids and spiders with 1.1 and 0.52 respectively per plant observed at Vetapalem and Chinaganjam mandals respectively.
Management studies revealed that thiamethoxam 25 % WG was found effective against thrips and leafhoppers with 65.07 and 60.25 per cent reduction of thrips and leafhoppers respectively over control. Thiacloprid 480 SC was found effective in reduction of aphids with 57.09 per cent reduction over control. Spinosad 45 SC was found to be effective in the reduction of leaf miner larval population and its per cent damage by 66.78 and 38.24 per cent reduction over control respectively.
Emamectin benzoate 5 SG was found effective in reducing the larval population of S. litura and its per cent damage by 66.95 and 33.98 per cent reduction over control respectively. Emamectin benzoate 5 SG was found effective in reduction of the larval population of bud borer and its damage by 69.85 and 35.85 per cent reduction over control respectively.
Chlorantraniliprole, cyantraniliprole and flubendiamide resulted in highest per cent reduction of 37.58, 37.27, 34.66 per cent reduction of coccinellids over control and these found harmful to coccinellids. Cyantraniliprole, flubendiamide and chlorantraniliprole resulted in highest per cent reduction of spiders 34.45, 32.14 and 31.93 per cent over control and found harmful to the spiders.
Among the treatments, spinosad 45 % SC recorded highest yield of 6.25 kg per plot (3125 kg/ha) with an increase of 92.48 per cent yield over control with highest cost benefit ratio of 1.45 over the other treatments. However, all the treatments were found significantly superior over untreated control both in terms of pest suppression and yield in groundnut.
Description
D5921
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