Abstract:
Disease management model for late blight (Phytophthora infestans) of tomato (Rorna YF.) was
developed to increase productivity. The experiment was conducted during the winter season of
2001-2002, in the field laboratory of the Department of Plant Pathology, BAU, Mymensingh,
following Randomized Complete Block Design (RCBD) comprising six replications with
combination of treatments viz; T, (control: no management); T1 (sanitation: removal of disease
parts from plants), T, (using fungicide, Ridomil MZ-68 @ 0.2%) and T. (combined use of
sanitation with fungicide spray). Significant differences were observed among the treatments
regarding disease incidence, severity and fruit yield. The highest disease incidence (88.34%) and
severity (84.33%) were recorded at 90 days after treatment in control (T,). The combined effect of
sanitation with spraying fungicide (T.) reduced late blight disease incidence and severity by
96.22% and 90.65%, respectively over control. The highest fruit yield 80.66 t/ha was obtained by
T. compared with the lowest (41.80 t/ha) in control (T,). The combined application of sanitation
with fungicide spray increased 93.01 % fruit yield over control. The benefit cost ratio (BCR)
resulted the lowest (8.15) in T, treatment and the highest (23.87) in T, treatment. Cost benefit
analysis showed that the T. gave a marginal return of 46.66% higher yield over control.
