STUDIES ON POD BORERS AND THEIR MANAGEMENT ON SOYBEAN WITH SPECIAL REFERENCE TO Cydia ptychora (Meyrick)
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Date
2015-05
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University of Agricultural Sciences, Dharwad
Abstract
Studies on seasonal incidence of pod borers revealed that Cydia ptychora (Meyrick) and Etiella zinckenella (Treitschke) were found infesting soybean during kharif-2014. The pink pod borer infestation commenced on 34th Meteorological Standard Week i.e. first week of September in both the varieties which attained a peak population (10.20 and 9.10 larvae/plant) on 42nd MSW. The commencement of E. zinckenella infestation was on 33rd MSW in JS 335 whereas, it was on 34th MSW in DSb 21 and reached a peak population (1.00 and 0.70 larvae/ plant) on 42nd MSW. The varieties sown during first week of June recorded minimum pod damage of 5.26 per cent by C. ptychora whereas July sown crop recorded maximum pod damage of 42.70 per cent. The correlation studies indicated that morning relative humidity exhibited a significant and negative correlation (r = -0.64**) with the incidence of C. ptychora in variety JS 335, whereas a highly significant and negative correlation (r = -0.71**) in variety DSb 21.
Out of ten released varieties screened for resistance to C. ptychora, DSb 21, RKS 18, MACS 1394 and DSb 23-2 were moderately resistant by recording 4.10, 7.00, 6.23 and 5.20 larvae/plant, respectively and under maximin-minimax method, varieties DSb 21, RKS 18, MACS 1394, DSb 23-2 and MAUS 61 were classified as tolerant high yielding.
Among the insecticides, chlorantraniliprole 20 SC (0.2 ml/l) was effective for managing C. ptychora (2.93 larvae/plant) with highest B:C ratio of 2.32 followed by flubendiamide 480 SC (0.5 ml/l) (3.97 larvae/plant) with B:C ratio of 2.12. Among the biorationals, nimbecidine 3000 ppm (3 ml/l) was the best treatment which resulted in 50.41% reduction over control, followed by novaluron 10 EC (1 ml/l) (44.63%).
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