Abstract:
The study was conducted in the laboratory of the Department of Entomology, Sher-eBangla
Agricultural
University,
Dhaka
from
May
2018
to
October
2018
to
find
the
most
preferable
grain
by
rice
weevil
(Sitophilus
oryzae
L.) based on its biology and the most
effective botanical insecticide to control the rice weevil in storage condition. The
experiment was laid out in the ambient condition of the laboratory following in a
Completely Randomized Design (CRD) and the treatments were replicated for four times.
Among the grains (wheat, husked rice, unhusked rice, maize and chick pea) considering
wheat, rice weevil was given the highest number of progenies for all 1
generation (90.33, 130.67 and 195.33). All the other grains resulted significantly different
number of progeny but the lowest was obtained from unhusked rice grain (78.33 and
113.33) for 1
st
and 2
nd
generation and 185.33 from maize at 3
ii
rd
generation. The highest
number of rice weevil larvae (5.67) was found in wheat grains. Number of adults were
highest 35.33 in wheat grains while the lowest in husked rice (11.67). According to the
observations, neem leaf powder (67.67 dead rice weevil) showed significantly very high
insecticidal effect on Sitophilus oryzae adults at 1 day after treatment application.
Mehogoni leaf T
1
(51.67 dead rice weevil), marigold leaf T
3
(48.67 dead rice weevil) and
garlic powder T
4
(34.67 dead rice weevil) were followed by neem leaf. Percent mortality
of some botanical insecticides, neem leaf T
2
st
, 2
(4% dead rice weevil), garlic powder T
4
(3%
dead rice weevil) and marigold leaf T
3
(2.33% dead rice weevil). The highest weight of
healthy seeds was recorded in T
2
(96.40 g) treatment which was statistically similar with
T
1
(91.28 g), whereas the lowest in T
6
(79.76 g) untreated control treatment. In case of %
infestation, the highest infestation was found from T
6
(19.96%) which was followed by
T
5
(15.82%) treatment while the lowest in T
2
(3.18%) treatment. The highest percent
infestation reduction over control was recorded in T
2
(84.07%) treatment and lowest from
T
5
(20.84%) treatment. So, from the above findings, it can be said that neem leaf powder
was found the best one to control rice weevil infestation as well as wheat grains were the
most preferred host for rice weevil.
Description:
A Thesis
Submitted to the 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
