Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu
Many vegetable transplants are being grown in greenhouses across Delmarva. Potential for disease can be minimized in many ways:
- *use certified tested and treated seed (even organic vegetable growers can treat with hot water or bleach solutions)
- *walls, benches, hand tools, pots and trays should be sanitized with 5% commercial bleach
- *weeds should be eliminated
- *new (or sterilized) potting mix should be used
- *seedlings should be watered early in the day so that the foliage dries quickly and, if possible, watered at the seedling base to reduce moisture on leaves
- *provide good air circulation and exchange in the greenhouse to minimize periods of high humidity
However, even after careful sanitation and good greenhouse management practices, disease may develop. Most fungicides are not labeled for greenhouse use.
The following table, which is modified from the Vegetable Management Guide 2008-2009 New England Region, is a good summary of available fungicide options and the diseases that they manage. Please note that Ridomil is not labeled for use in the greenhouse. Use only labeled fungicides or biofungicides. Read the label carefully because if a product is not applied properly, phytotoxicity may occur.
Follow this link for the table: “Fungicides and Bactericides Labeled for Vegetable Bedding Plants (pdf)”