Abstract:
An experiment was conducted in the experimental field of Sher-e-Bangla
Agricultural University, Dhaka, Bangladesh during the period from May, 2018 to
September, 2018 to evaluate some botanicals applied against major insect pests of
summer cabbage. The experiment was laid out in Randomized Complete Block
Design (RCBD) with three replications .Seven treatments, viz., T
1
(Mahogany
seed kernel extract @ 3.0 ml/L of water at 7 days interval); T
2
(Tobacco leaf
extract @ 3.0 ml/L of water at 7 days interval); T
3
(Garlic extract @ 3.0 ml/L of
water at 7 days interval); T
4
(Neem leaf extract @ 3.0 ml/L of water at 7 days
interval); T
5
(Neem seed kernel extract @ 3.0 ml/L of water at 7 days interval); T
6
(Neem oil @ 3.0 ml/L of water at 7 days interval) and T
7
(untreated control) were
used. Among the management practices, the lowest mean infestation of cabbage
leaf by semi-looper (4.79 leaves/5 plants), tobacco caterpillar (6.25 leaves/5
plants) and diamond back moth larvae 4.39 leaves/5 plants) was found in T
6
that
reduced highest leaf infestation over control (59.40%, 61.73% and 68.03%
respectively); whereas the highest infestation by semi-looper (11.80 leaves/5
plants), tobacco caterpillar (16.33 leaves/5 plants) and diamond back moth larvae
(13.73 leaves/5 plants) was found in T
7.
The lowest mean incidence of semi-looper
(5.47 larvae/5 plants), tobacco caterpillar (9.17 larvae/5 plants) and diamondback
moth (3.30 larvae/5 plants) was found in T
6
that reduced highest incidence over
control (65.09%, 49.97% and 66.57% respectively); whereas the highest values of
all these parameters were recorded from untreated control treatment (T
7
).The
lowest cabbage head infestation(13.00%) was recorded in T
6
, that gave the highest
yield of cabbage (36.50 tha
-1
) followed by T
4
(31.83 tha
-1
). From the study it was
found that there is a strong negative relationship between leaf infestation intensity
and single head weight and between leaf infestation intensity and yield (tha
) of
cabbage. Moreover, a strong negative relationship was observed between percent
head infestation and weight of individual head at harvest.
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
