Abstract:
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
Description:
A field experiment was carried out in the central farm of Sher-e-Bangla Agricultural
University, Dhaka, Bangladesh during October 2019 to March 2020.The experiment was
conducted to evaluate the effect of selected chemicals, micronutrients and botanicals in
controlling purple blotch complex of onion. The experiment was laid out in a Randomized
Complete Block Design (RCBD) with three replications and local variety faridpuri was used
as a planting material. In this experiment, three fungicides viz. Indofil, Mancer and Ridomil
Gold, three micronutrients viz. Zinc, Boron and Magnesium and two botanical extracts
namely neem and eucalyptus were used to evaluate their effect on disease incidence, percent
disease index, number of leaves per plant,leaf length, bulb diameter, bulb weight (fresh and
dry) and yield. Among the treatments, chemical fungicide Ridomil Gold gave better
performance in comparison to other treatments. Data was recorded at 70, 80 and 90 days
after transplanting and it was found that the lowest disease incidence (52.67%) and percent
disease index (49.00%) was recorded in Ridomil Gold treated plots with the highest number
(9.77) and length (43.43cm) of leaf. It was also found that the highest bulb diameter (18.23
cm), single bulb weight (47.98 g), fresh weight (3.16 Kg/plot), dry weight (2.88Kg/plot)
were also obtained from Ridomil Gold treated plots. This treatment also gave the highest
yield (9.60 t ha
-1
) followed by Indofil (8.20 t ha
ii
-1
) and Mancer (7.90 t ha
-1
). Among the nine
treatments, Ridomil Gold also increased yield by 54.34% over control treatment. Boron and
eucalyptus leaf extract was given satisfactory results in all considering parameters tested in
the experiment. However, chemical fungicide performed better than micronutrients and
botanical leaf extracts.
