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Subject: Entomology × Author: Balabantaray, Suchismita × End date: 2018 × Start date: 2016 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Population build up and management of whitefly in cotton under variable weather and fertilizer conditions
    (CCSHAU, 2017) Balabantaray, Suchismita; Jaglan, R. S.
    A field experiment entitled “Population build up and management of whitefly in cotton under variable weather and fertilizer conditions” was conducted during kharif season of 2016 at Entomology Research Area of CCS Haryana Agricultural University, Hisar. The studies revealed that whitefly adults population reached two peaks on 37th and 38th SMW (i.e. 2nd and 3rd weeks of September) with 6.11 and 5.96 adults per leaf, whereas nymphs population was as high as 8.44 and 8.74 nymphs per leaf during 36th and 37th SMW (i.e. 1st and 2nd weeks of September), respectively. Whitefly adults had significant positive relation with maximum temperature (r=0.728) and bright sunshine hours (r=0.808) but significant negative correlation with morning (r= -0.699), evening relative humidity (r= -0.625) and rainfall (r= -0.786) and nymphs population was found to have significant positive correlation with maximum temperature (r=0.642) and bright sunshine hours (r=0.781) but negative significant relation with morning relative humidity (-0.639) and rainfall (-0.699). All weather variables collectively accounted for 81, 69 and 65 per cent variability in the adults, nymphal and natural enemies populations. The whitefly adults and nymphs population was maximum at late sown crop on 20th June (4.96 adult and 5.96 nymphs/leaf) and on crop treated with excess dose of nitrogen fertilizer (5.89 adult and 8.1 nymphs/leaf). Among nine treatments T8 (Neem Baan 1500 ppm @ 1.0 l/acre + thiamethoxam 25 WG @ 40 g /acre + Neem Baan 1500 ppm @ 1.0 l/acre) was better, where the minimum population of adults and nymphs were found during 3rd DAS (1.89 adults/leaf), 5th DAS (1.78 adults/leaf), 7th DAS (2.11 adults/leaf) and 7th DAS (8 nymphs/leaf) but T1 was found safest to the natural enemies with 1.89 per plant natural enemies population and had highest BC ratio (1.17).