Abstract:
The experiment was conducted in the experimental field of Sher-e-Bangla
Agricultural University, Dhaka-1207, during November 2019 to February 2020 to
find out the optimum time of insecticide application in mustard field to reduce
mortality rate of the natural pollinating agents of mustard. The experimental design
was a split-plot design with three replicates and two factors Factor A: Main factor;
Mustard crop bordered by other crops T
1
- Mustard bordered by Dill (Shova), T
2
-
Mustard bordered by Linseed (Neela), T
3
- Mustard bordered by Coriander (BARI
Dhonia-1), T
4
- Mustard bordered by Niger and T
5
- Mustard without border crop
(Control); Factor B: Second factor; insecticide: Actara 25WG@ (0.3gm/L; at the
15 days intervals) application timing where S
1
- Spray insecticide at 8.30 am, S
2
-
Spray insecticide at 11.30 am, S
3
- Spray insecticide at 2.30 pm and S
4
- Spray
insecticide at 5.00 pm. Effect of insecticide application time of pollinators was
calculated and it was revealed that mustard plants with border crops were greatly
influenced by the presence of different pollinators which increase crop yield.
Diversity of insect pollinators was observed and among others presence of honey
bee was observed as most frequently visited pollinators (33,24). The ShannonWeaver
diversity
index
in
mustard
field
bordered
with
Niger
for
species
was
1.87,
16.4
% community dominance observed species in mustard field bordered with
Niger. Total seed weight/plant of mustard significantly influenced by different
pollination conditions with the influence of bordered crops. The highest seed
weight/plant (1123 g) was recorded from treatment T
4
- Mustard bordered by Niger.
The lowest seed weight/plant (922.70 g) was recorded from treatment T
5
– Mustard
without border crop (Control). The optimum time of insect pollinator foraging was
observed at 11.30 am and the least number of insect pollinator observed at 5.00 pm,
insecticide application should be at 5.00 pm to avoid minimum pollinator drifting.
Application of any insecticides at 5.00 pm affect lowest to the insect pollinators
population.
Description:
A Thesis
Submitted to the Department of Entomology
Faculty of Agriculture,
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE (MS)
IN
ENTOMOLOGY
