Monitoring of major insect pests associated with green gram [Vigna radiata (L.) Wilczek] and their management
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Date
2022
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DRPCAU, PUSA
Abstract
The present research entitled “Monitoring of major insect pests associated with green gram [Vigna radiata (L.) Wilczek] and their management” was carried out at Research Farm, T.C.A., Dholi during the summer season 2022. The green gram variety HUM 16 was taken as a test variety for the research programme. During the course of my studies, the observations recorded to six species as major pests on green gram. Whitefly and jassids were first observed during the 12th standard week 21 days after sowing (0.37 whiteflies/ three leaves and 0.50 jassids/ three leaves) which increased gradually and attained its peak population (5.53 whiteflies/ three leaves and 5.70 jassids/ three leaves) during the 15th standard week, the incidence of thrips on the 13th standard week 28 days after sowing (0.83 thrips/ 10 flower buds) followed by spotted pod borer started (1.33 larvae/ 10 plants) during the 14th standard week. After that, Pod bug and gram pod borer populations began to infest the green gram (2.50 pod bugs/plant and 0.67 larvae/ 10 plants, correspondingly) (15th SMW). The population of insect pests at its maximum was found in the crop in (16th SMW) in whiteflies (6.00), jassids (8.03) and thrips (15.10). The highest population of pod bug (5.43), spotted pod borer (8.45) and gram pod borer (3.33) were noted during the 18th standard week. After that, it was noted that the population was decreasing trends during crop maturity stage.
The study found the major insect pests were positively correlated with maximum and minimum temperature but negatively with relative humidity, except gram pod borer was favourable association with evening relative humidity. Pod bug, spotted pod borer, and gram pod borer populations were positively correlated with rainfall, while whitefly, jassids, and flower thrips populations were negatively correlated with rainfall.
All the treatments are were found significantly superior over untreated control. Among all the treatments T1 flubendiamide 480 SC (0.1 ml/l) was discovered to be more efficient at suppressing the larvae population of Maruca vitrata and Helicoverpa armigera on the green gram, it was ranging from 54.18 to 76.63 per cent and 49.25 to 75.27 per cent reduction over control followed by T4 indoxacarb 14.5 SC (0.3 ml/l). The lowest amount of pod damage was noticed in flubendiamide 480 SC 4.00 per cent treated plot followed by indoxacarb 14.5 SC 4.33 per cent and the maximum was found in NSKE (5%) treated plots.
The flubendiamide 480 SC treatment obtained the highest grain yield (915 kg/ha), which is statistically superior to all other treatments. indoxacarb 14.5 SC {13.23:1} had the highest incremental cost-benefit ratio and was at par with emamectin benzoate {10.33:1}.