Phytophthora blight typically develops in low-lying areas after a heavy rain. Fortunately, this spring in New Jersey has been really dry – too dry thus far, but that does not need you don’t need to prepare for potential phytophthora issues down the road. This is particularly important if are in fields with a known history of Phytophthora blight. Although extended periods of dry weather works against Phytophthora development, it can lead to Rhizoctonia root rot issues in newly transplanted plugs, especially if those plugs remain on the dry side too long before watering. Symptoms of Rhizoctonia root rot appear as brown lesions at the base of the stem with those lesions eventually girdling the stem and extending about an inch above the soil surface. If transplants haven’t been treated the the cell flat prior to transplanting, apply a fungicide through the drip system soon after transplanting.
Recommendations for Rhizoctonia control
Apply azoxystrobin (FRAC group 11) at labelled rates.
Recommendations for Phytophthora blight control
In general, planting on a ridge or raised, dome-shaped bed will help provide better soil drainage. In fields with known low-lying or wet areas, avoid transplanting in those areas all together. In fields with a known history of Phytophthora blight, plant ONLY resistant 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.
| Code | Product Name | Product Rate
|
Active Ingredient(s)
(*=Restricted Use) |
PHI
(d) |
REI
(h) |
Bee
TR |
| For control of the CROWN ROT phase of Phytophthora blight, apply one of the following at transplanting and 30 days later. | ||||||
| 4 | MetaStar 2E AG | 4.0 to 8.0 pt/A1 | metalaxyl | 7 | 12 | N |
| 4 | Ridomil Gold 4SL | 1.0 pt/A1 | mefenoxam | — | — | N |
| 4 | Ultra Flourish 2E | 1.0 qt/A1 | mefenoxam | — | — | N |
| 21 | Ranman 400SC | 2.75 fl oz/A2,3 | cyazofamid | 0 | 12 | L |
| 43 | Presidio 4SC | 3.0 to 4.0 fl oz/A3 | fluopicolide | 2 | 12 | L |
| 49 + 4 | Orondis Gold 1.67SC | See labels1,2,4 | oxathiapiprolin + mefenoxam | 0 | 4 | — |
Recommendations for Organic Growers
Organic bell pepper growers with a history of the Phytophthora blight should only plant cultivars that have resistance or tolerance to the disease. Long non-host crop rotations are critically important for organic production. Regular applications of Double Nickel (Bacillus amyloliquefaciens) or Regalia (Extract of Reynoutria sachalinensis) as drenches or via the drip system prior to the onset of disease may help suppress Phytophthora blight development.
