STUDIES ON SEASONAL INCIDENCE, VARIETAL SCREENING AND MANAGEMENT OF MAJOR INSECT PESTS OF FRENCH BEAN (Phaseolus vulgaris L.)
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Date
2018-07
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University of Horticultural Sciences, Bagalkot (COLLEGE OF HORTICULTURE, BENGALURU)
Abstract
Studies on seasonal incidence, varietal screening and management of major insect pests of French bean (Phaseolus vulgaris L.) were conducted in open field condition with protective irrigation at Horticulture Research and Extension Centre, Hogalagere, Srinivasapura taluk, Kolar district, Karnataka during Kharif 2017. Twelve species of insect pests belonging to orders Lepidoptera (2 species), Hemiptera (6 species), Thyasanoptera (1 species), Coleoptera (2 species) and Diptera (1 species) were recorded on French bean. Peak activity of thrips (Megalurothrips usitatus Bagnall) was noticed during 44th standard meterological week (SMW) and Helicoverpa armigera (Hübner) during 44thSMW. Maximum activity of Myllocerus discolour F. was observed during 39th SMW and Clavigralla gibbosa Spinola during 43rd SMW. Peak activity of Anoplocnemis phasiana F. and Eurybrachys tomentosa F. during 44th SMW. Incidence of Maruca vitrata (Geyer) damage was peak during 43rd SMW. Minimum temperature and morning and evening relative humidity had positive correlation with incidence of M. usitatus. The increase in morning and evening relative humidity had positive correlation with H. armigera, Myllocerus discolor and pod bugs (C. gibbosa, A. phasiana and E. tomentosa). Population of M. vitrata had positive correlation with rainfall, morning and evening humidity. Among different genotypes evaluated, L7P1 recorded maximum green pod yield (11.56 kg/ 4m2) as well as lower per cent flower (12.18) and pod damage (5.29) by M. vitrata, followed by Arka suvidha (11.11 kgs/ 4m2) and L5P1 (10.88 kg/ 4m2) compared to remaining genotypes. The maximum pod yield (10.98 t/ha) and minimum infestation (52.36%) by M. vitrata was recorded in thiamethoxam 25 WG (0.25 g/l), followed by spinosad 45 SC (0.3 ml/l) and profenophos 50 EC (2 ml/l) over other treatments. The C:B ratio was highest in profenophos 50 EC (1:4.81) and thiamethoxam 25 WG (1:4.35) treatments.