With the wet weather, conditions for the crown rot phase of Phytophthora blight have increased. Phytophthora blight typically develops in low-lying areas of fields after a heavy rain and can spread quickly throughout the entire field. Planting on a ridge or raised, dome-shaped bed will help provide better soil drainage.
Use a minimum 3-year crop rotation with crops other than peppers, cucurbits, lima and snap beans, eggplants, or tomatoes. In fields with low-lying or wet areas, plant only Phytophthora-tolerant cultivars such as ‘Paladin’, ‘Aristotle’, ‘1819’, or ‘Revolution’. In heavily-infested fields with a known history of Phytophthora blight, plant only tolerant cultivars to help reduce plant losses. If mefenoxam-insensitivity is known to exist in a field/farm, plant only tolerant cultivars. Do not apply mefenoxam or metalaxyl in fields where insensitivity is known to exist.
For control of the crown rot phase of Phytophthora blight, apply:
mefenoxam–1.0 pt Ridomil Gold 4SL/A
or
1.0 qt Ultra Flourish 2E/A
or
metalaxyl (MetaStar)–4.0-8.0 pt 2E/A at transplanting and 30 days later
or
Presidio (fluopicolide, 43) at 3.0-4.0 fl. oz 4SC/A,
or
Ranman (cyazofamid, 21) at 2.75 fl oz 400SC (Ranman may be added to transplant water, see label for restrictions).
Phosphite materials (FRAC code 33) such as Rampart, ProPhyt, K-Khite may also be applied with one of the above to help suppress Phytophthora blight