EFFECT OF FIPRONIL AND LAMBDA CYHALOTHRIN ON COLONY PERFORMANCE OF Apis mellifera UNDER FIELD AND SEMI-FIELD CONDITIONS IN ONION (Allium cepa L.)
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Date
2023-01
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UHF,NAUNI
Abstract
ABSTRACT
The present investigation “Effect of fipronil and lambda cyhalothrin on colony performance of
Apis mellifera under field and semi-field conditions in onion (Allium cepa L.)” was conducted during the
period 2020-2021. The effect of spray of fipronil 80 WG @ 0.12g/l and lambda-cyhalothrin 5% E.C @ 0.85g/l
on onion bloom, was evaluated on foraging activity, mortality and colony performance viz., brood area, nectar
stores, pollen stores and bee strength of A. mellifera under field and semi-field (cage) conditions. The contact,
oral toxicity and larval toxicity of these chemicals to A. mellifera and A. cerana was also evaluated under
laboratory conditions. Under semi-field conditions, the foraging activity of A. mellifera significantly reduced to
6.50 bees/m2/2 min in fipronil and 1.55 bees/m2/min in lambda cyhalothrin on the day of spray. No significant
difference among the day hours in the foraging activity was observed. In comparison to the colony parameters,
one day before introduction of the colonies to different treatments, significantly low brood area could be seen on
7th and 14th day and significant reduction in nectar and pollen area on 7th day. Overall comparison of brood area
and nectar area among the treatments indicated significantly higher brood area in control followed by lambdacyhalothrin
and fipronil. Significant decrease in pooled bee mortality was recorded up to 3rd day after exposure
to fipronil and 2nd day after exposure to lambda- cyhalothrin under semi-field conditions. Overall average bee
mortality was significantly higher (45.66 bees/day) in fipronil followed by lambda cyhalothrin (18.30 bee/day)
exposure followed by control (6.94 bees/day). Under field conditions, sharp decline in A. mellifera activity after
spray of fipronil (5.83 bees/day) and lambda-cyhalothrin (5.77 bees/day) was recorded as compared to control.
Significant recovery in bee activity was observed on 10th and 9th day after spray in fipronil and lambdacyhalothrin
treatments. The brood area decreased non significantly on 7th day and significantly thereafter in
fipronil exposure, whereas effect of lambda-cyhalothrin was not much pronounced. Non-significant variations
were found in pollen area under the influence of both the chemicals under field conditions. A significant decline
in bee strength on 7th day after exposure to fipronil and non- significant decline under the effect of lambdacyhalothrin
was recorded. The contact toxicity and oral LD50 of fipronil and lambda-cyhalothrin to A. mellifera
adults was 0.005, 0.052 and 0.040μg/bee and 0.83μg/bee whereas in A. cerana adults it was 0.006, 0.046 and 0.
04, 0.501 μg/bee, respectively after 24 hours exposure period under laboratory conditions. As observed in the
present investigations the foraging activity and colony parameters of A. mellifera was negatively affected under
field and semi-field conditions. Fipronil and lambda cyhalothrin have lethal and sublethal effects on colony
performance of A. mellifera at the field relevant doses and should be applied in a restricted manner.