Abstract:
The experiment was conducted in the experimental area of Sher-e-Bangla
Agricultural University, Sher-e-Bangla Nagar, Dhaka during the period from
November 2014 to May 2015 to evaluate the efficacy of some management
practices against insect pest complex of BRRI dha50. BRRI dhan50 were used
as the test crop in this experiment. The experiment comprised of the following
control measure as treatment- T1 = Spraying Diazinon 60EC @ 2ml/Litre of
water sprayed at 7 days interval; T2 = Spraying Suntap 50 WP @ 1.2g/Litre of
water at 7 days interval; T3 = Applying Mechanical control at 7 days interval; T4
= Applying Cultural control at 7 days interval and T5 = Untreated control. The
experiment was laid out in a randomized complete block design (RCBD) with
three replications. Data was recorded on pest incidence, number of healthy,
infested plants & leaf for different pests and infestation level and also yield
contributing characters and yield of BRRI dhan50 and significant variations was
observed for different treatments. Data revealed that 8 common species of insect
pests were found in rice field and they were belongs to 7 family under 6 orders.
Among the insect species 2 species belong to the family Pyralidae. Insect
population for 5 selected hills/plot were observed with clean observation and in
the experimental plot yellow stem borer, leaf folder, rice hispa, grasshopper,
brown plant hopper, green leaf hopper, rice bug and rice stink bug was observed
and the highest number of the insect pests was recorded from T5, whereas the
lowest number of these insect pests was observed from T2 treatment. In case of
tillers, leaf and panicle infestation in different crop stages caused by different
rice insect pests, the lowest infestation was recorded from T2, whereas the
highest infestation was observed from T5. In consideration of yield contributing
characters and yield of BRRI dhan50, the maximum number of filled grains
(93.74) was recorded from T2, while the minimum number of filled
grains/panicle (84.77) from T5. The highest grain yield (5.67 t/ha) was recorded
from T2, while the lowest grain yield (3.35 t/ha) from T5. Among the different
control measures, spraying Suntap 50 WP @ 1.2g/ Litre of water at 7 days
interval was the better for the controlling of insect pest complex of BRRI dha50.
Description:
A Thesis
Submitted to the Faculty of Agriculture
Sher-e-Bangla Agricultural University, Dhaka
in partial fulfilment of the requirements
for the degree
of
MASTER OF SCIENCE (MS)
IN
ENTOMOLOGY
SEMESTER: JANUARY-JUNE, 2015