Abstract:
A field experiment was conducted at the central farm of Sher-e- Bangla Agricultural
University, Dhaka-1207, during March to July, 2017. The aim of the study was to
investigate the varietal performance of two popular okra varieties namely BARI
Dherosh-1 and Green finger against Okra yellow mosaic virus (OYMV) by controlling
the insect vectors with Imidacloprid and light reflecting silver color mulch. Two
experiments were carried out in two blocks layouted with RCBD and four treatments
viz. T
0
(control/no spray), T
1
(only mulching), T
2
(1 spray+ mulching) and T
(3 times
spray) with three replications. The mulch was used at 15 DAS and insecticide was
sprayed at 30 DAS and continued with 15 days interval. At 95 DAS, the lowest
disease incidence (%) was estimated in T
(one spray+ mulching) that were 34.72 %
and 19.65 % in BARI Dherosh-1 and Green finger respectively. The highest disease
incidence (%) was estimated in T
0
2
(untreated/control) that was 73.71 % in BARI
Dherosh-1 and 51.11 % in Green finger. In case of morphological parameters; the
highest number of leaves, flowers and fruits per plant was recorded in T
(one spray+
mulching) and that was 46.33, 9.33, 7.00 in BARI Dherosh-1 and 48.00, 12.33, 10.67
in Green finger respectively up to last harvesting. Yield and yield contributing
characters were significantly varied among the treatments. The highest yield per plant
and plot was obtained in T
(one spray+ mulching) treatment in case of both varieties
(0.15 kg/plant, 2.86 kg/plot in BARI Dherosh-1 and 0.24 kg/plant, 4.37 kg/plot in
Green finger). The highest plant height was also found in T
2
(one spray+ mulching) in
both varieties (128.62 cm and 130.33 cm respectively). It was also observed that when
percent disease incidence increased, the yield of okra was also decreased. However,
considering the economic conditions/cost-benefit ratio T
2
2
(one spray+ mulching) gave
the best results in terms of controlling the insect vector whitefly.
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
IN
PLANT PATHOLOGY
