- Cucurbit downy mildew was reported on cucumber in Salem County on 7/3. This is the first report of CDM in the state this year. All cucurbit growers should scout on a regular basis and add a downy mildew specific fungicide to their regular maintenance program. To track cucurbit downy mildew in the US please visit http://cdm.ipmpipe.org/
- Late blight was found on potato and processing tomato in Salem county on 7/2. All potato and tomato growers who have not initiated a protectant fungicide program should do so. All growers should consider adding a late blight specific fungicide to their program as long as the current weather pattern sticks around. To track late blight in the US please visit http://usablight.org/
- Timber rot (AKA white mold) and Botrytis (AKA grey mold) have been reported on field-grown tomato this week.
Cucurbit downy mildew – Scout a daily basis. Downy mildew typically appears first on cucumber in our region and then jumps to the other cucurbit crops in the following weeks. Downy mildew is much easier to control if fungicides have been applied prior to its arrival. Once downy mildew is detected in the region (or state) all cucurbit growers should include a downy mildew specific fungicide in their weekly maintenance program. Downy mildew specific fungicides include: Ranman (cyazofamid, 21) at 2.1 to 2.75 fl oz. 400SC/A, Presidio (fluopicolide, 43) at 3.0 to 4.0 fl oz. 4SC/A (caution, pathogen may be less sensitive to Presidio than in past year’s), Previcur Flex (propamocarb, 28) at 1.2 pf 6F/A, Zampro (ametoctradin + dimethomorph, 43 + 40) at 14.0 fl oz. 525SC. Other materials for use as tank mix partners include: Phosphite (33) such as K-Phite, Prophyt or Rampart; Tanos (famoxadone + cymoxanil, 11 + 27) at 8.0 oz. 50WP/A, Forum (dimethomorph, 40) at 6.0 fl oz. 4.18SC, or Curzate (cymoxanil, 27) at 3.2 oz. 60DF/A. Always rotate fungicides from different FRAC groups to help reduce the chances for resistance development. Organic growers should scout their cucurbit plantings on a regular basis and apply an OMRI-approved copper based fungicide or other labeled product to help suppress the development of cucurbit downy mildew. Adequate and repeated spray coverage of the bottom of all leaf surfaces is critical for the control of cucurbit downy mildew in commercial and organic cucurbit production. It is important to remember that control of downy mildew begins with planting resistant cucumber varieties when possible. No other cucurbits have resistance to downy mildew. Once harvesting is finished, all fields or blocks should either by plowed under, mowed down or burnt down with gramoxone to reduce potential sources of inoculum.
For current 2013 Cucurbit Downy and Powdery Mildew Management FRAC Table and Guidelines please see post from 6/7/13. Additional information on the control of cucurbit downy and powdery mildew can be found in the 2013 Commercial Vegetable Production Recommendations.
Pepper – Phytophthora blight – Plant loss can be severe in all pepper types. 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 when conditions favor disease development, 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.
Potato – Late blight – The protectant fungicides below should be applied prior to the arrival of the disease.
chlorothalonil (M5) at 1.0 to 1.5 pt 6F/A or OLF, mancozeb (M3) at 1.5 to 2.0 lb 75DF/A or OLF. (Note: DO NOT apply more than a total of 15.0 pounds per acre per crop), or Polyram (M3) at 2.0 lb 80DF/A or OLF. (Note: DO NOT apply more than a total of 15.0 pounds per acre per crop).
The following fungicides can be used when the threat of the disease is high or present in the area and protectant fungicides have been used prior to disease occurrence:
Curzate (cymoxanil, 27) at 3.33 oz 60DF/A plus a protectant fungicide (i.e., chlorothalonil or mancozeb),
Forum (dimethomorph, 40) at 4.0 to 6.0 fl oz 4.18SC/A plus a protectant fungicide,
Gavel (zoxamide + mancozeb, 22 + M3) at 1.5 to 2.0 lb 75DF/A
Omega (fluazinam, 29) at 5.5 fl oz. 500F/A
Presidio (fluopicolide, 43) at 4.0 fl. oz 4SC/A
Previcur Flex (propamocarb, 28) at 1.2 pt 6F/A plus a protectant fungicide
Ranman (cyazofamid, 21) at 1.4 to 2.75 fl oz 400SC/A
Revus (mandipropamid, 40) at 5.5 to 8.0 fl oz 2.08SC/A
Revus Top (mandipropamid + difenconazole, 40 +33) at 5.5 to 7.0 fl oz 4.16SC/A
Tanos (famoxadone + cymoxanil, 11 + 27) at 6.0 to 8.0 oz 50W/A plus a protectant fungicide
When a field contains new late blight infections and harvest is near, vines should be destroyed immediately to help prevent tuber infection.
Tomato – Late blight – Protectant following protectant fungicides should be applied prior to the arrival of the disease.
chlorothalonil (M5) at 1.0 to 3.0 pt 6F/A or OLF, Gavel (zoxamide + mancozeb, 22 + M3) at 1.5 to 2.0 lb 75DF/A, or mancozeb (M3) at 3.0 lb 75DF/A or OLF.
Once late blight is detected in your area, tank mix one of the following translaminar fungicides with a protectant fungicide. Rotate between one of the following tank mixtures:
Curzate (cymoxanil, 27) at 3.2 to 5.0 oz 60DF/A plus a protectant fungicide
Forum (dimethomorph, 40) at 6.0 fl oz 4.18SC/A plus a protectant fungicide
Presidio (fluopicolide, 43) at 3.0 to 4.0 fl oz 4SC/A plus a protectant fungicide
Previcur Flex (propamocarb, 28) at 1.2 pt 6F/A plus a protectant fungicide
Ranman (cyazofamid, 21) at 2.10 to 2.75 fl oz 400SC/A plus a protectant fungicide
Reason (fenamidone, 21) at 5.5 to 8.2 fl oz 500SC/A plus a protectant fungicide
Revus Top (mandipropamid + difenconazole (40 + 3) at 5.5 to 7.0 fl oz 4.16SC/A plus a protectant fungicide (Not for use on small fruited varieties)
Tanos (famoxadone + cymoxanil, 11 + 27) at 8.0 oz 50WG/A plus a protectant fungicide
In greenhouse settings late blight can be particularly damaging. A strong scouting and preventative fungicide program is essential to reduce potential impacts. Microclimate management to reduce levels of free moisture on foliage is essential to reduce disease spread. The following materials permit greenhouse applications. You should consult fungicide labels to ensure greenhouse applications are permitted.
The following materials can offer suppression and are labeled for greenhouse application, apply one of the following:
Heritage (azoxystrobin, 11) at 1.6 to 2.0 oz 50WG/A
Catamaran (chlorothalonil + phosphite M5 + 33) at 5.5 to 7.0 pt 5.3F/A
