Although conditions have been favorable, No Late blight has been reported in New Jersey this past week.
Basil
Downy mildew remains active – All basil growers should scout on a daily basis and should add a labeled downy mildew specific fungicide to their weekly fungicide program. Phosphite fungicides (FRAC code 33), such as Prophyt, K-Phite, and Rampart have shown the best efficacy in trials at RAREC. Actinovate (OMRI- approved) is also labeled for downy mildew control. Please remember, all abandoned basil fields should be worked under immediately after last harvest to kill the foliage! Abandoned fields left unattended after use will only serve as a source of inoculum for other fields.
Cole crops
Downy mildew and Alternaria – Symptoms of downy mildew include purple to yellowish-brown spots on upper leaf surfaces. A grayish-white spore mass will develop and cover the underside of leaves under ideal temperatures (night temperatures of 46 to 61°F and day temperatures below 75°F). Downy mildew can kill young plants. Heavily infected leaves may drop providing entry points for bacterial infections (i.e., black rot and soft rot). Symptoms of Alternaria on infected leaves include small, expanding circular lesions with concentric rings that may have a ‘shot-hole’ appearance as lesions age. Heavily infected seedlings may result in damping-off. Control of Downy mildew and Alternaria begin with preventative fungicide applications. Use one of the following at the first sign of disease and continue every 7 to 10 days (Please refer to the pesticide table on page F27 of the 2013 NJ Commercial Vegetable Production Recommendations to determine which fungicide is labeled for each specific crop.): Quadris (azoxystrobin, 11) at 6.0 to 15.5 fl oz 2.08SC/A, or chlorothalonil (M5) at 1.5 pt 6F/A or OLF, or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 oz 20EG/A, or Endura (boscalid, 7) at 6.0 to 9.0 oz 70WG/A, or Ridomil Gold Bravo (mefenoxam + chlorothalonil, 4 + M5) at 1.5 lb 76.5WP/A, Fontelis (penthiopyrad ,7) at 14.0 to 30.0 fl oz 1.76SC/A, or Switch (cyprodinil, 9) at 11.0 to 14.0 oz 62.5WG/A (Alternaria only). For downy mildew only, apply Actigard (acibenzolar-S-methyl, P) at 1.0 oz 50WG/A (begin applications 7-10 days after thinning and re-apply every 7 days for a total of 4 applications per season), or Aliette (fosletyl Al, 33) at 3.0 to 5.0 lb 80WDG/A (on 14-day schedule).
Cucurbit downy mildew remains active in New Jersey
Continue to scout all cucurbit crops on a regular basis. Cucurbit downy mildew was reported on muskmelon in Ohio and on squash this past week. Please see the 2013 Commercial Vegetable Recommendations Guide for specific fungicide recommendations. To track the progress of cucurbit downy mildew please visit North Carolina State University’s Cucurbit Downy Mildew Forecasting Center at http://www.ces.ncsu.edu/depts/pp/ cucurbit/.
Cucurbit powdery mildew
Cucurbit growers should adjust fungicide programs accordingly. Remember, cucurbit powdery mildew is favored by hot, dry weather.
Peppers
Anthracnose fruit rot – Heavy rain and wind can cause pepper anthracnose to flare up. Growers with peppers in fields with a history of pepper anthracnose should scout on a daily basis and apply fungicides preventatively. Pepper anthracnose can be very difficult to control once established. Strip picking and removing all fruit from ‘hot spots’ when they first appear may help suppress spread of the pathogen. Preventative fungicide applications should begin shortly before or at flowering. Use a heavy volume of water and make sure coverage is extremely good. Apply high rates of chlorothalonil or Manzate weekly and/or rotate weekly with Quadris (azoxystrobin, 11) or Cabrio (pyracolostrobin, 11). Please see the 2013 New Jersey Commercial Vegetable Production Recommendations Guide for more information.
