Abstract:
The experiment was conducted in the experimental area of Sher-e-Bangla Agricultural
University, Sher-e-Bangla Nagar, Dhaka during the period from April to August 2016,
to evaluate the effect of different doses of nitrogen fertilizer (urea) on the incidence of
sucking insect pest of rice. BRRI dhan43 were used as the test crop in this experiment.
The experiment comprised of the following nitrogen doses as treatment- T1 = Top
dressing of Nitrogen fertilizer (urea) @ 50kg/ha at three equal split application; T2 =
Top dressing of Nitrogen fertilizer (urea) @ 60kg/ha at three equal split application; T3
= Top dressing of Nitrogen fertilizer (urea) @ 70kg/ha at three equal split application;
T4 = Top dressing of Nitrogen fertilizer (urea) @ 80kg/ha at three equal split
application; T5 = Top dressing of Nitrogen fertilizer (urea) @ 90kg/ha at three equal
split application and T6 = Untreated control. The experiment was laid out in a
randomized complete block design (RCBD) with three replications. Data was recorded
on insect pest incidence, number of healthy, infested plants, leaf and tillers due to
different insect pests and infestation level and also yield contributing characters and
yield of BRRI dhan43 from different treatments. It was revealed that 3 common species
of sucking insect pests such as brown plant hopper, green leaf hopper and rice bug were
found in rice field. Insect populations for 5 selected hills/plot were observed and
sucking insect pests e.g., brown plant hopper, green leaf hopper and rice bug were
investigated. In case of tillers, leaf and panicle infestation in different crop stages
caused by different rice sucking insect pests, the lowest infestation was recorded from
T3, whereas the highest infestation was observed from T5. In consideration of yield
contributing characters and yield of BRRI dhan43, the maximum number of filled
grains/panicle (93.38%) was recorded from T3, while the minimum number of filled
grains/panicle (73.36%) from T6. The highest grain yield (4.25 t/ha) was recorded from
T3, while the lowest grain yield (1.24 t/ha) was recorded from T6 followed by T5
(2.55t/ha). Among the different nitrogen doses; 70 kg N/ha applied in T3 treatment was
superior to other nitrogen doses.
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, 2016