Sweet Corn

European corn borer (ECB) moth catches have remained steady at very low levels over the past week.   At this time, activity is highest in Gloucester and Camden counties (see ECB map at left).  Catches are widely dispersed.   Above threshold (12%) larval infestations continue into the northern counties.  Larval infestations should be expected to continue for another week or so.

The highest nightly trap catches of ECB for the week ending 7/01/20 are as follows:

Corn earworm (CEW) moth captures stayed largely unchanged in blacklight traps this past week.   This lingering population is somewhat heavier than normal for this time of year, and silking corn will need protection from this pest.  Blacklight catches were highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 7/01/20 are as follows:

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• Cucurbit powdery mildew season is here. For a review of CPM control strategies please click here.
• Cucurbit downy mildew has been reported on cucumber in western MI and as far north as North Carolina on cucumber. For a review of CDM control please click here. To track the progress of CDM on your phone or PC please visit the CDM forecasting website.
• No reports of Late blight in region. To track the progress of Late blight in the US please click here.
• Basil downy mildew (BDM) has been reported in southern New Jersey on BDM susceptible sweet basil. All growers are encouraged to initiate preventative fungicide programs on DMR and non-DMR basil. For control options and to follow the progress of BDM in the US on your phone or PC please click here.
• Bacterial canker has been reported in fresh-market tomato. For a review of bacterial canker in tomato please see report by Dr. Sally Miller at The Ohio State University by clicking here.
• Diplodia leaf streak, a fungal disease, was identified in sweet corn this past week. Symptoms include the development of numerous pycnidia which produce conidia within the lesions on infected corn leaves. For nice reviews, please see report by Dr. Kiersten Wise and colleagues from the University of Kentucky and report by Dr. Steve Johnson at the University of Maine.
• White mold, caused by Stromatina cepivorum, has been reported in garlic. For more information, please see report by Crystal Stewart and Frank Hay from Cornell University.
• Angular leaf spot has been reported in summer squash. Look for angular lesions delimited by leaf veins and ‘shotholes’ in infected leaves that develop after periods of hot, dry weather.
• Phytophthora blight has been reported in pepper and cucurbit crops.
• Rhizoctonia and Pythium root rot have been reported in pepper. For a review of identifying and controlling root rots please click here.
• Septoria leaf spot and bacterial blight have been reported in parsley.
• Timber rot, or white mold, has been reported in tomato.
• White rust and Cercospora have been reported in spinach.
• Bacterial leaf spot has been reported in sweet basil. BLS of sweet basil is a relatively new disease of basil in the US. The bacterium has a large host range and can survive and overwinter in the soil on infested plant debris. Disease development is favored by hot, humid, rainy weather. Periods of hot, dry weather will help mitigate disease development.
• Sand blasting has been reported on a number of leafy green and other crops these past few weeks. Injury from sand blasting predisposes plants to bacterial infections. Remember, all bacteria need a wound or a natural opening, such as a stomata, to gain entry into the plant. Fields with extensive injury need to be scouted regularly, and most likely will need to be sprayed regularly with a copper fungicide or disinfectant-type product to help mitigate infection and spread.
• For a review on how to avoid sunscald injury on transplanted crops please click here.
• With the on and off again heavy rains we have been getting, along with warmer weather, all growers should consider applying at-transplanting fungicides for root rot control. Please click here to see these articles.
• The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online! With many county offices running reduced hours or being closed this is the easiest way to obtain the newest recommendations.
• For a quick review on managing fungicide resistance development using tank mixes and fungicide rotations, and information on FRAC group 4, FRAC group 7, and FRAC group 3 and FRAC group 11 fungicides please click on hyperlinks.

Sweet Corn

European corn borer (ECB) moth catches have declined somewhat over the past week.   At this time, activity is highest in Gloucester County and along the Cape May/Cumberland bay shore (see ECB map at left).  Catches are widely dispersed.   Larval infestations above 20% continue into the northern counties this past week.  Larval infestations should be expected to continue for approximately another 2 weeks.

As always, look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample.  As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left).  It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time.  This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.

Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen.  Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn.  Control with these materials is very inconsistent.

The highest nightly trap catches of ECB for the week ending 6/24/20 are as follows:

Corn earworm (CEW) moth captures increased slightly in blacklight traps this past week.   As early plantings are now in the silk stage, they will need protection from this pest.  Blacklight catches sere highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 6/24/20 are as follows:

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