Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu
The following is a checklist of cultural practices to manage Phytophthora crown rot and blight. Also, remember that the pathogen can survive and thrive in surface water. If fields are irrigated with pond water that is infested with Phytophthora capsici, they will become infested. Likewise, under flooding conditions, infested ditch water can spread the disease. Pond water for irrigation can be tested for the presence of Phytophthora capsici, and if infested, filtered.
Reminder: Never use fungicides as the only means of managing the disease.
Integrated Management Strategies -Field Preparation
□ Crop Rotation- minimum of 3 years.
□ Plant only well-drained sites.
□ Avoid planting low areas of fields.
□ Subsoil or V-rip fields prior to planting to break up hardpan.
□ Use dome-shaped beds for peppers and squash. (Raised beds reduce accumulation of high moisture around the bases of plants.)
□ Raised beds should be made with a Kennco-type bed maker to achieve long-lasting beds with a crown.
□ Use a bed-shaper to build stable beds. Do not build a loose ridge!
□ Beds should be a minimum of 9 inches high.
□ Poly mulch will not reduce blight incidence by itself.
□ Use resistant pepper varieties and gourd-type pumpkins with hard rinds (e.g. L’l Ironsides) whenever possible.
□ Avoid over-irrigation.
□ Do not enter fields with wet foliage.
□ Rogue Phytophthora infected plants when found.
□ Promptly till infected debris at the end of the season.
□ Never dump culls or diseased fruit from other fields or farms into production fields. (Once Phytophthora capsici is introduced, it may remain indefinitely.)
□ Pond water can harbor Phytophthora. Test your water and, if P. capsici is present, use a filter and treatment that is effective on Phytophthora.
□ Construct drainage ditches to aid drainage of excess water after heavy rains.