Investigations on the Population Dynamics, Estimation of Losses and Management of Major Insect Pests of Soybean [Glycine max (L.) Merill.]
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Date
2006
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MPUAT, Udaipur
Abstract
Investigations on the population dynamics, estimation of losses and management of major insect pests of soybean [Glycine max. (L.) Merril.) was carried out during kharif,2003 and 2004 in the Department of Agricultural Zoology and Entomology, Rajasthan College of Agriculture, Udaipur. The results revealed that soybean crop in sub humid Southern plain Zone IVa was attacked by jassid, Amrasca kerri Pruthi; white fly, Bemisia tabaci Gennadius, tobacco caterpillar Spodoptera litura Fab., grey weevil Myllocerus undecimpustulatus Faust and stem fly, Melanagromyza sojae Zehntner pests. The incidence of jassid, A. kerri; white fly, B. tabaci and M. sojae was initiated in the second week of August and attained their peaks in first week of September (36 Standard Meteorological Week), in third week of September (38 Standard Meteorological Week) and fourth week of August (34 Standard Meteorological Week) respectively. While, tobacco caterpillar, S. litura and grey weevil, M. undecimpustulatus population commenced in the fourth week of August (34 Standard Meteorological Week) and fifth week of August (35 Standard Meteorological Week) respectively. The grey weevil reached to its peak in fourth week of September (39 Standard Meteorological Week) while, tobacco caterpillar in the first week of October (40 Standard Meteorological Week). All the pests except stem fly showed a positive correlation with the mean temperature and mean relative humidity.
The insect pests infestation significantly reduced viz; plant height, number of pods/plant, test weight (1000 seeds), seed yield /plant, husk yield /plant, seed and husk yield /plot, in protected and unprotected plot in variety of JS-335 of soybean. The average seed yield of soybean obtained in protected and unprotected plot was 21.13 & 22.86 and 13.37 & 15.33 q/ha, respectively which depicted that insect pests of soybean caused an average loss of 35.92 and 32.79 per cent equivalent to 7.76 and 7.53q/ha during 2003 and 2004, respectively.
The results of bio efficacy experiments revealed that the schedule comprising spray of imidacloprid 200 SL @ 125 ml/ha at 40 days after sowing followed by spray of endosulfan 35EC (0.07%) at 60 days after sowing (M5) was most effective against all the insect pests of soybean. It also yielded the highest mean seed yield of 23.02 and 22.24/ha during kharif, 2003 and 2004, respectively. It was at par to seed treatment with imidacloprid @ 7 g/kg seed and spray of acephate 75WP (0.07%) at 60 days after sowing (M1), soil treatment with carbofuran 3G @ 25 kg/ha and spray of acephate 75WP (0.07%) at 60 days after sowing (M4) and spray of dimathoate 30EC (0.03%) at 40 days after sowing and spray of endosulfan 35EC (0.07%) at 60 days after germination (M8). The schedule comprises of seed treatment of imidacloropid 70 WS @ 7g/kg seed followed by spray of neem seed oil 5% at 60 days after sowing (M2) and spray of spinosad @ 225ml/ha at 40 days after sowing followed by neem seed oil 5% at 60 days after sowing (M7) were the next effective schedules.
The management schedule comprises of 2 releases of Chrysoperla carnea Stephens eggs at 40 and 60 days after sowing (M6) was the least effective schedule. However, integration of C. carnea release at 60 days after sowing with soil treatment of carbofuron 3G @ 25 kg/ha was found more effective than 2 release of C. carnea alone.
Description
Investigations on the Population Dynamics, Estimation of Losses and Management of Major Insect Pests of Soybean [Glycine max (L.) Merill.]
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Citation
Padiwal and Rana, 2006