RISK ANALYSIS OF NEWER INSECTICIDE MOLECULES ON SAFETY OF HONEY BEES, Apis cerana indica FABRICIUS (HYMENOPTERA: APIDAE)
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Date
2017-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Horticultural Sciences, Bagalkot. (College of Horticulture, Bengaluru).
Abstract
In toxicity analysis of newer insecticide molecules on Apis cerana indica, bees
were exposed to six selected insecticide molecules through bioassay and oral
(contaminated pollen and nectar) and contact exposure (insecticide drift and residual
toxicity) Since honeybees are considered as one of the potential pollinators, bee
losses results in the reduction of crop yield due to the indiscriminate use of
insecticides in the field. Results from the bioassay experiment suggested that
thiamethoxam, emamectin benzoate, fipronil, spinosad, cyantraniliprole and
chlorantraniliprole exhibited acute toxicity with LC50 of 0.0003 μg a.i. ml-1
,
0.0006 μg
a.i. ml-1
, 0.003 μg a.i. ml-1
, 0.277 μg a.i. ml-1
, 4.864 μg a.i. ml-1
and 21.776 μg a.i. ml1
respectively and the mortality increased with LC50 value of 0.0002, 0.00031,
0.00097, 0.028, 2.648 and 3.239 0.0002 μg a.i. ml-1
at 48h post treatment. The
purpose of this work is to fix LC50 value for the selected insecticides under laboratory
conditions through bioassay method in the honeybee. The experimental analysis
indicated that none of the insecticides are safer for honeybees. Results obtained
from oral toxicity indicated that thiamethoxam caused highest mortality of 63.33%
followed by emamectin benzoate (62.50%), cyantraniliprole (51.67%),
chlorantraniliprole (49.99 %), fipronil (47.50%) and spinosad (42.50%). The mortality
from evaluation of insecticide drift indicated that highest mortality was obtained in
thiamethoxam (78.00%) followed by fipronil (73.33%), chlorantraniliprole (59.52%),
cyantraniliprole (59.05%), emamectin benzoate (57.81%) and spinosad (50.19%).
The contact toxicity of insecticide residues conducted in cashew ecosystem indicated
that mortality of honeybees reduced in correspondence with decrease in day of
insecticide treatment.