EFFECT OF NEONICOTINOIDS ON COLONY PERFORMANCE OF Apis mellifera L. IN MUSTARD

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dc.contributor.advisorSHARMA, HARISH KUMAR
dc.contributor.authorRAM, BUDHI
dc.date.accessioned2018-12-22T09:43:23Z
dc.date.available2018-12-22T09:43:23Z
dc.date.issued2018-09
dc.description.abstractABSTRACT The present study was conducted to assess the effect of neonicotinoids on colony performance of Apis mellifera L. in mustard. The study was conducted under field, semi field and laboratory conditions during 2017-2018. Under field (thiamethoxam @ 0.1g/l) and semi field conditions (thiamethoxam @ 0.1g/l and imidacloprid @ 0.3ml/l) was sprayed on mustard bloom to evaluate the effect on foraging activity, brood area, nectar stores, pollen stores and mortality of foragers. Laboratory studies were conducted to establish the contact and oral toxicity of thiamethoxam and imidacloprid to A. mellifera adults and larvae. Under field conditions, average quantum of bee activity of A. mellifera remained statistically low upto 12th day (3.51 to 8.56 bees/m2/5min) after spray of thiamethoxam on mustard bloom in comparison to pre-count (18.44 bees) and control (17.11 to 19.19 bees). Unlike foraging activity, non significant effect on average nectar, pollen stores and bee strength in thiamethoxam treated plots during the period of observations in comparison to pre-count. The average bee mortality of A. mellifera was significantly higher on 1st (112.5 bees/DBT/day) 2nd (112 bees) and 3rd day (46.33 bees) after spray in comparison to mortality observed in control. In semifield studies, foraging activity of A. mellifera on mustard bloom reduced significantly on 2nd day after spray of thiamethoxam (3.22 bees/m2/5min) and imidacloprid (2.21 bees) as compared to pre-count and control (37.65 bees). Significant recovery was recorded in the activity of A. mellifera on 6th day in thiamethoxam (6.14 bees/m2/5min) and imidacloprid (10.23 bees) after spray. Activity of A. mellifera in both the treatments (thiamethoxam and imidacloprid) remained statistically low upto 8th day after spray, which thereafter became normal and statistically same with pre-count and control by the 10th day after spray. Thiamethoxam and imidacloprid spray in mustard also affected colony parameters of introduced A. mellifera, which leads to significant decrease in brood area (7th to 21st day), nectar stores (7th to 28th day) and pollen stores (7th to 21st day) and increased significantly on 28th day after spray. The mortality of A. mellifera was significantly higher on 1st and 2nd day after spray of thiamethoxam (293 and 231.83 bees/DBT/day) and the same trend was also recorded in imidaclprid (70.17 and 74bees) spray in comparision to control (4.17 and 9.83). The contact toxicity of thiamethoxam and imidacloprid to A. mellifera adults was 0.019 and 0.037 µg/bee, respectively after 24 hours exposure period under laboratory conditions. The oral LD50 was recorded 0.0038 and 0.006µg/bee after ingestion of 2 µl of sugar syrup contaminated with thiamethoxam and imidacloprid, respectively within an exposure period of 24 hours. Thus it has been concluded from the present investigations that foraging activity of A. mellifera was negatively affected in both the fields, colony parameters (only in semi field conditions) and also mortality was higher in treated mustard crop suggesting that neonicotinoids have sublethal and lethal effects on colony performance of A. mellifera at the field relevant doses. Hence, it is suggested that neonicotinoids namely thiamethoxam and imidacloprid should be applied in a restricted manner to conserve the natural biodiversity.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810086239
dc.keywordseffect of neonicotinoids, colony performance, mustarden_US
dc.language.isoenen_US
dc.pages115+XIXen_US
dc.publisherUHF, NAUNIen_US
dc.subEntomologyen_US
dc.subjectnullen_US
dc.themeeffect of neonicotinoids, colony performance, mustarden_US
dc.these.typePh.Den_US
dc.titleEFFECT OF NEONICOTINOIDS ON COLONY PERFORMANCE OF Apis mellifera L. IN MUSTARDen_US
dc.typeThesisen_US
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