TY  - BOOK
AU  -  Shiralli Hareesh 
AU  - Guruprasad G. S. 
TI  - Toxicological Effects of Insecticides to Indian Honeybee, Apis Cerana Indica Fabricius With Special Reference to Neonicotinoids                             
U1  - 595.7 
PY  - 2024///
CY  - Dharwad
PB  - University of Agricultural Sciences, Dharwad
N2  -             Investigations on in vitro and in vivo lethal toxicity of selected insecticides especially neonicotinoids, to the Indian honeybee (Apis cerana indica) were carried out at College of Agriculture, Department of Entomology, Dharwad (Karnataka, India) during 2021-2024. The research also involved the estimation of pesticide residues in honey samples collected from agro-climatic zones of Karnataka and evaluated the activity of detoxifying enzymes in bees exposed to selected insecticides. In vitro lethal toxicity was assessed using three bioassay methods: oral ingestion, indirect contact and topical application. Among neonicotinoids, imidacloprid 17.8 SL was the most toxic irrespective of methods with LC50 values (0.26, 0.54, and 0.33 ppm) and safety index (0.52, 1.08, and 0.66) in oral, indirect contact and topical applications respectively. Acetamiprid was the least toxic neonicotinoid with LC50 values (1.29, 1.89, and 1.07 ppm) and higher safety indices (6.45, 9.45, and 5.35), suggesting its relatively safer profile. Among non-neonicotinoid insecticides, carbaryl 50 WP emerged as the most toxic in all three bioassay methods with least LC50 values of 0.52, 0.57 and 0.38 ppm in oral, indirect and topical method, respectively. In contrast, bio-rational insecticides azadirachtin 0.3%, buprofezin 25 SC and green-labelled insecticide chlorantraniliprole 18.5 SC appeared to be less toxic to honeybees across all three bioassay methods, as indicated by their higher LC50 values. 445.75, 410.43 and 50.98 ppm (oral method), 354.29, 340.16 and 81.14 ppm (contact method) and 222.60, 90.28 and 1.77 ppm (topical method) respectively. Further, safety of five insecticides on honeybees was assessed at MARS, Dharwad and Karadigudda with onion crop. Higher per cent bee mortality was observed in colonies exposed to onion crop treated with acetamiprid and thiamethoxam compared to buprofezin, azadirachtin or untreated crop. Foraging activity and hive parameters like pollen, brood and honey storage were significantly better in buprofezin and azadirachtin treatments comparable to untreated control while acetamiprid and thiamethoxam treatments negatively influenced these parameters. This highlights the need to reconsider the application of these insecticides during blooming periods, especially in onion crop. Honey samples analysed using LC-MS/MS and GC-MS/MS for 69 and 38 pesticide mixtures revealed no detectable residues in apiary honey across Karnataka except for samples from insecticide-treated plots. Residues of acetamiprid (4.046 mg/kg), thiamethoxam (6.252 mg/kg) and buprofezin (2.679 mg/kg) were detected while azadirachtin-treated and control plots could not revealed any residues. Estimated Daily Intake (EDI) and Hazard Index (HI) values for detected pesticides were below acceptable limits indicating no acute health risks from honey consumption. Further, enzyme activity analysis showed that honeybees exposed to azadirachtin and buprofezin exhibited higher levels of detoxifying enzymes suggesting lower toxicity. In contrast, neonicotinoids and carbaryl treatments showed minimal enzyme activity, indicating higher toxicity. These findings underscore the need for careful insecticide selection to safeguard pollinators and ensure safe honey production.


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