Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
For control of the crown rot phase of phytophthora blight in pepper:
Apply 1.0 pt Ridomil Gold 4SL/A or 1.0 qt Ultra Flourish 2E/A (mefenoxam, 4), or MetaStar (metalaxyl, 4) at 4.0 to 8.0 pt 2E/A. Apply broadcast prior to planting or in a 12- to 16-inch band over the row before or after transplanting. Make two additional post planting directed applications with 1 pint Ridomil Gold SL or 1 qt Ultra Flourish 2E per acre to 6 to 10 inches of soil on either side of the plants at 30-day intervals. Use formula titled “Calibration for Changing from Broadcast to Band Application” from Calibrating Granular Application Equipment in Section E of the Delaware Commercial Vegetable Production Recommendations to determine the amount of Ridomil Gold needed per acre when band applications are made. When using polyethylene mulch, apply Ridomil Gold 4SL at the above rates and timing by injection through the trickle irrigation system. Dilute Ridomil Gold 4SL prior to injecting to prevent damage to injector pump. Do not use mefenaoxam or metalaxyl if insensitive strains of Phytophthora capsici are present.