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Subject: Entomology × Author: Jasjinder Kaur × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Ecological impact of neonicotinoids on arthropod fauna of Bt cotton
    (Punjab Agricultural University, Ludhiana, 2017) Jasjinder Kaur; Vijay Kumar
    The studies on ‘Ecological impact of neonicotinoids on arthropod fauna of Bt cotton’ confirmed presence of 78 species of arthropods comprising predators, non-target, casual visitors, sucking pests and pollinators (33.33, 25.64, 19.23, 12.82 and 8.98%) at Bathinda. During 2015, diversity of sucking pests was higher in acetamiprid 20SP and dinotefuran 20SG while it was higher in imidacloprid 17.8SL and thiamethoxam 25WG; acetamiprid 20SP, dinotefuran 20SG and clothianidin 50WDG in 2016 after first, second and third spray. Diversity was lower in imidacloprid and thiamethoxam in both years. In predatory fauna and non targets, higher diversity was recorded in imidacloprid 70WS and thiamethoxam 30FS as compared to other treatments. Diversity of pollinators was higher in imidacloprid 70WS and thiamethoxam 30FS and in recommended doses of other neonicotinoids while it was lower in double doses of neonicotinoids. Mean population of whitefly, thrips, red cotton bug, dusky cotton bug and predatory species was minimum in acetamiprid @ 100 g/ha while jassid was minimum in dinotefuran 20SG @ 250g/ha and pollinators in clothianidin 50 WDG @ 60g/ha. The experiment on development of Chrysoperla zastrowi sillemi revealed longer larval period in acetamprid 20SP @ 50 g/ha when fed on neonicotinoid treated jassid (13.89 and 13.83 days) and whitefly (13.61 and 12.95 days) while it was minimum in imidaclorpid 70WS during 2015 and 2016, respectively. The number of jassid nymphs and whitefly adults consumed by larva was maximum in imidacloprid 70WS (286.40, 302.13 and 264.93 and 273.20), respectively in both the years whereas it was minimum in acetamprid 20SP @ 50 g/ha (250.47, 278.80 and 224.07, 246.20). The third experiment on ‘Residual effect of neonicotinoids on development of Bemisia tabaci’ revealed significantly higher fecundity in imidacloprid 17.8SL @ 50 g/ha (79.20 and 82.33 eggs/2 pairs) and lower in dinotefuran 20SG @ 125 g/ha (43.13 and 49.07 eggs/2 pairs) during 2015 and 2016, respectively. Minimum nymphal duration was recorded in imidacloprid 17.8SL @ 100 g/ha (12.99 and 12.06) and maximum in dinotefuran 20SG @ 125 g/ha (15.43 and 14.41 days). The growth index was significantly lower in dinotefuran 20SG @ 100 and 125 g/ha (4.26, 4.24 and 4.35, 4.12) during 2015 and 2016, respectively.