Sweet Corn

European corn borer (ECB) adults continue to be very low, although a few traps in Cape May and Burlington counties have shown initial signs of a second flight.  Numbers are low and isolated such that no map will appear in this edition.

The highest nightly trap catches of ECB for the week ending 7/29/20 are as follows:

Fall armyworm (FAW) larval infestations are generally low, but IPM technicians report more frequent occurrences in the central counties.   This is the time of the summer when FAW can show up, resulting in significant injury to whorl and even seedling stage corn.  Injury from newly hatched larvae shows up as “window panes” or areas where leaf tissue has been eaten down the the lower epidermis (see photo at far left).  This injury leads down into the whorl.  As larvae gain size, they begin to consume leaf tissue in its’ entirety, creating ragged holes and lots of droppings (see photo at near left).  FAW can be tough to manage because it is resistant to synthetic pyrethroid insecticides (IRAC 3A) and because larvae are often covered by their own droppings, making contact with the insecticide more difficult.  Treat when 12% or more plants exhibit FAW injury alone, or in combination with ECB injury.

Corn earworm (CEW) moth captures have remained largely unchanged in blacklight traps this past week.  This moderate mid-Summer population poses a significant risk to silking corn.  Blacklight catches were highest overall along the Atlantic coast (see map at left), with blue areas on this map representing a 4-5 day spray schedule.

The highest nightly trap catches of CEW in black light traps for the week ending 7/29/20 are as follows:

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Sweet Corn

European corn borer (ECB) adults continue to be very low, and no map will appear in this edition.

The highest nightly trap catches of ECB for the week ending 7/22/20 are as follows:

Fall armyworm (FAW) larval infestations are light and widely scattered.   This is the time of the summer when FAW can show up, resulting in significant injury to whorl and even seedling stage corn.  Injury from newly hatched larvae shows up as “window panes” or areas where leaf tissue has been eaten down the the lower epidermis (see photo at left).  This injury leads down into the whorl.  As larvae gain size, they begin to consume leaf tissue in its’ entirety, creating ragged holes and lots of droppings (see photo at right).  FAW can be tough to manage because it is resistant to synthetic pyrethroid insecticides (IRAC 3A) and because larvae are often covered by their own droppings, making contact with the insecticide more difficult.  Treat when 12% or more plants exhibit FAW injury alone, or in combination with ECB injury.

Corn earworm (CEW) moth captures increased in blacklight traps this past week.   Although the increased numbers do not represent a large influx, they do pose an elevated risk to silking corn.  Blacklight catches were highest overall along the Delaware Bay (see map at left), with blue areas on this map representing a 4-5 day spray schedule.

The highest nightly trap catches of CEW in black light traps for the week ending 7/22/20 are as follows:

[Read more…]

• Cucurbit downy mildew has been reported on cucumber in southern New Jersey. This is the first report in the state this growing season. There have been no reports of CDM in other cucurbit crops in the region to date. 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.
• Cucurbit powdery mildew (CPM) season is here. For a review of CPM control strategies please click here.
• All cucurbit plantings that are no longer in production should be destroyed immediately after the last harvest by mowing or with herbicide to reduce the risk of harboring of CDM, CPM, and virus.
• Virus has been reported in summer squash plantings.
• Pepper anthracnose has been reported in southern New Jersey and is a serious problem in all bell and non-bell peppers, especially in fields with a history of the disease. For more information on controlling pepper anthracnose please click here.
• No reports of Late blight in region. To track the progress of Late blight in the US please click here.
• Collar rot caused by Alternaria has been reported again in tomato this week in New Jersey. It is the same pathogen that causes Early blight in tomato. Tomato growers who have not switched to more specific fungicides for Early blight and anthracnose fruit rot control should consider doing so. For more information from NCSU please click here.
• Heavy infections of Angular leaf spot have been reported in summer squash this week. Look for angular lesions delimited by leaf veins and ‘shotholes’ in infected leaves that develop after periods of hot, dry weather.
• Aerial stem rot has been reported on potato in southern New Jersey. The pathogen is an opportunistic bacterium in the field which infects vines that have been damaged by wind and heavy rains.
• There have been a few reports of Southern blight (Sclerotinia rolfsii) on tomato and pepper. Southern blight is much more common in vegetable areas south of the state where summer temperatures remain hotter (above 90°F) for longer periods of time. Like white mold, caused by Sclerotinia sclerotiorum, it can survive in the soil for many years. Symptoms of Southern blight include infection at the base of the stem at the soil-line. The resulting infection will girdle the plant causing wilt and death. The fungus will produce white, cottony mycelium and very small, spherical sclerotia which are often have a white to tannish, brown color as they mature. For more information on Southern blight from NCSU please click here.
• Rhizoctonia root and crown rot has been reported on sugar beet in southern New Jersey. For more information from the University of Idaho please click here.
• Bacterial leaf spot has been reported in pepper. For more information on BLS and copper resistance please click here.
• Phytophthora blight has been reported in pepper and cucurbit crops. For more information 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.
• Downy mildew has been reported in kale seedlings in a hydroponic greenhouse in PA. As a note, kale and related crops should be scouted on a regular basis. For more information on downy mildew in brassica crops from UMASS-Amherst 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.
• 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.
• 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.
• 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.
• For more information on the control of the diseases mentioned above please see The 2020/2021 Commercial Vegetable Production Recommendations Guide which 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.

Sweet Corn

European corn borer (ECB) adults have all but disappeared over the past week, and no map will appear in this edition.    Larval infestations are sparse now, as the last corn plantings to be exposed to ECB in the whorl now have entered the silk stage.

The highest nightly trap catches of ECB for the week ending 7/15/20 are as follows:

Fall armyworm (FAW) has declined, and larval infestations are no longer evident in the northern counties.  There are still low infestations in Cape May County, and moths are being captured there as well as near the Burlington/Camden County border.  This is the time of the summer when FAW can show up, resulting in significant injury to whorl and even seedling stage corn.  Injury from newly hatched larvae shows up as “window panes” or areas where leaf tissue has been eaten down the the lower epidermis (see photo at left).  This injury leads down into the whorl.  As larvae gain size, they begin to consume leaf tissue in its’ entirety, creating ragged holes and lots of droppings (see photo at right).  FAW can be tough to manage because it is resistant to synthetic pyrethroid insecticides (IRAC 3A) and because larvae are often covered by their own droppings, making contact with the insecticide more difficult.  Treat when 12% or more plants exhibit FAW injury alone, or in combination with ECB injury.

Corn earworm (CEW) moth captures remained steady at reasonably low levels in blacklight traps this past week.   Despite these lower counts,  silking corn continues to require protection from this pest.  Blacklight catches remain highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 7/15/20 are as follows:

[Read more…]

Sweet Corn

European corn borer (ECB) moth catches have fallen to very low levels over the past week.   Remaining activity is highest in Gloucester and Camden counties (see ECB map at left).  Threshold (12%+) level larval infestations are declining now, as the last corn plantings to be exposed to ECB in the whorl now are entering the silk stage.  Larval infestations should decline sharply until the second flight appears.

The highest nightly trap catches of ECB for the week ending 7/08/20 are as follows:

Fall armyworm (FAW) larvae have appeared in low numbers in fields in Cape May County, as well as in Hunterdon and Morris counties.  This pest seems to have arrived last week some time, and has since subsided somewhat.  This is the time of the summer when FAW can show up, resulting in significant injury to whorl and even seedling stage corn.  Injury from newly hatched larvae shows up as “window panes” or areas where leaf tissue has been eaten down the the lower epidermis (see photo at left).  This injury leads down into the whorl.  As larvae gain size, they begin to consume leaf tissue in its’ entirety, creating ragged holes and lots of droppings (see photo at right).  FAW can be tough to manage because it is resistant to synthetic pyrethroid insecticides (IRAC 3A) and because larvae are often covered by their own droppings, making contact with the insecticide more difficult.  Treat when 12% or more plants exhibit FAW injury alone, or in combination with ECB injury.

Corn earworm (CEW) moth captures have declined in blacklight traps this past week.   Despite lower moth levels,  silking corn continues to require protection from this pest.  Blacklight catches remain highest overall along the coast (see map at left).

The highest nightly trap catches of CEW in black light traps for the week ending 7/08/20 are as follows:

[Read more…]