Abstract:
The experiment was conducted in Central MS laboratory and Central Farm of
Sher-e-Bangla Agricultural University, Dhaka-1207 during November 2019 to
May 2020 to evaluate the efficacy of some plant extracts in controlling leaf blight
of sunflower variety BARI Surjamukhi-2. The causal organism isolated from
infected leaf of sunflower and identified as Alternaria alternata by tissue
planting method. The field experiment was laid out in randomized complete
block design (RCBD) with three replications. The treatments consisted of plots
sprayed with T
1
=Control, T
2
=Neem leaf extracts, T
3
=Garlic bulb extracts,
T
4
=Mint leaf extracts, T
5
=Allamanda leaf extracts, T
6
=Papaya leaf extracts and
T
7
=Mahogany leaf extracts. Concentration of all plant extracts was 1:3 w/v. Data
were collected on disease incidence, percent disease index (PDI), plant height,
number of leaves per plant, stem girth, head diameter, number of seeds per head,
1000 seeds weight and yield. The lowest disease incidence (43.32%) with
maximum reduction (45.64%) of PDI over control was recorded in garlic bulb
extracts (T
3
) at 75 DAS. Garlic bulb extracts (T
3
) treated plots gave better
response in all growth, yield and yield contributing parameters viz., tallest plant
(132.4 cm), maximum number of leaves (28) per plant, thickest plant (5.47 cm),
maximum head diameter (17.78 cm), highest number of seeds (523) per head,
1000 seeds weight (57.46 g) and yield (778.87 g/plot). The maximum yield
increased (63.39%) over control was also recorded in garlic bulb extracts (T
3
)
followed by papaya leaf extracts (T
6
) and neem leaf extracts (T
2
). In this study it
was found that spray with garlic bulb extracts (T
3
) showed most effective in
controlling Alternaria leaf blight incidence, severity with increasing yield of
sunflower.
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
