DISEASE DEVELOPMENT, VARIATION IN PATHOGEN AND CHEMICAL CONTROL OF DOWNY MILDEW OF CUCURBIT
RV HIREMARTH and S ASHTAPUTRE
University of Agricultural Sciences, Drarwad, India
Background and objectives
Materials and methods Development of downy mildew at weekly interval was studied on four species of Cucurbitaceae sown on two different dates for 2 ;years. Cross inoculation was carried out in potted plants in glasshouse either by spray inoculation or by stapling infected leaves. Nineteen varieties belonging to nine species were inoculated with the inoculum obtained from six varieties of three species.
Fungicidal control of the disease was by Metalaxyl MZ (metalaxyl 8% + mancozeb 64%) spray at different stages.
Results and conclusion
Cross-inoculation studies indicated that the inoculum from different cucurbits was cross-inoculable to most other species of Cucurbitaceae, indicating that the fungus appears to be pathologically uniform. The possibility of existence of races within a geographical locality appears to be less likely.
Chemical control of Downy mildew on cucumber showed that the disease can be effectively controlled by seed treatment with Metalaxyl MZ followed by two sprays (0.1%) at 35 and 50 ;days after sowing.