For over a decade, basil downy mildew (BDM) has caused significant losses in basil grown in organic and conventional field and greenhouse production across the United States. At the time of its introduction, there were very few fungicides labeled for its control making it nearly impossible to grow a successful crop in many areas of the country. [Read more…]
Vegetable Crops Edition
Seasonal updates and alerts on insects, diseases, and weeds impacting vegetable crops. New Jersey Commercial Vegetable Production Recommendations updates between annual publication issues are included.
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July 2, 2022 Andy Wyenandt
Vegetable Disease Update: 07-02-22
- Powdery mildew has been reported in cucurbit crops. For more information on the control of CPM please click here.
- Cucurbit downy mildew has been reported on cucumber in southern New Jersey and Eastern PA. For more information on CDM control please click here.
- Bacterial leaf spot has been reported in pepper. More more information on BLS control please click here.
- Bacterial canker has been reported in tomato. For more information on diagnosing important tomato diseases please click here.
- Early blight has been reported on potato.
- Phytophthora blight has been reported on pepper. For more information please click here.
- Dickeya dianthicola has been reported in potato in Virginia and Massachusetts.
- The 2022/2023 Commercial Vegetable Production Recommendations Guide is available for free online or for sale in hardcopy form at many County offices.
- 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.
July 1, 2022 Melissa Bravo
Crop progress and sicklebarring palmer greenstalks
Salem County: Two plus inches of June precipitation on the 9th and 12th carried non-irrigated corn and soybean through the month with only trace amounts of precipitation until the 24th when some areas received another half inch.
In exceptionally wet fields, climbing humidity levels on the 13th, 14th, and 15th were high enough to allow for foliar disease development in beans.
But the following week of low humidity was less than conducive for disease proliferation until the 22nd through the 25th when humidity levels briefly rose and remained in the high 80’s and 90’s for three days, before dropping nicely to the mid 60’s the last two days of June. However, wind speeds of 15 to 25 mph from June 13th to June 19th wicked moisture out of corn and soybeans leaving the crops in a moisture deficit.
This is confirmed in ‘The Evaporative Demand Drought Index’ (EDDI) monitoring tool for South
-Jersey. This tool created by the NOAA Physical Science Laboratory is an indicator of both rapidly evolving “flash” droughts and sustained droughts. “EDDI can offer early warning of agricultural drought, hydrologic drought, and fire-weather risk.”
Pest pressure: Producers should monitor beans for Japanese beetle, green stink bug and grasshopper feeding going into July and be alert to excessive damage from flea beetles on crops stressed from wind evaporation. Palmer amaranth is exceptionally tolerant to droughty conditions and thrives under stresses that wilt other pigweed species. Shattercane and johnsongrass are both warm-season grasses that also thrive under these weather conditions.
Mechanical options: In addition to chemical control options, if droughty evaporative weather persists, producers should consider manually removing seedhead stalks to protect maximum yield projections in soybeans. The ideal mechanical tool to do this would be a front mounted sickle bar mower. Do-it-yourself fabricators maybe interested in this attachment created specifically to deal with palmer amaranth by a Kansas farmer. (A cooperative build, purchase, may be a good investment for combine and spray rig operators in the County). https://www.rowshaver.com/
Forecast: Going into this weekend, the 24-hour precipitation forecast for
New Jersey anticipates a tenth of an inch to half inch of rainfall for most of Salem County through July 3 and much-needed swath probable for the northern counties where drought conditions the last seven days are 51% to 75% below normal.
July 1, 2022 Andy Wyenandt
Identifying white mold in tomato production
White mold, or timber rot, is caused by the soil-borne fungal pathogen, Sclerotinia sclerotiorum.
High tunnel tomato plant with main stem infected by white mold.
The photo on right shows a high tunnel tomato plant with main stem infected by white mold. Over time the entire plant will slowly collapse looking similar to a wilt or root rot pathogen as the water supply is cut off to the plant.
White mold is common and once introduced into a field or high tunnel it can very difficult to control. The pathogen produces black sclerotia on the surface and inside infected stems. Sclerotia, if they make their way back into the soil, can survive for years causing significant problems.
Infected stems will turn a light brown color and dry up becoming brittle. If the main stem is infected the entire plant will collapse looking like a wilt or root rot issue.
Under hot, humid conditions white fungal growth will develop on the surface of the stems and in some cases sclerotia will develop on the outside of the stem. Breaking open the stem will reveal numerous black sclerotia.
All infected plants and or plant material need to be removed immediately and disposed of properly. Preventative protectant fungicide programs beginning at flowering will help control white mold. Cool, wet weather and poor air circulation favors disease development.
There are a number of control options for conventional and organic growers listed in Table E-11 in the 2022/2023 mid-Atlantic Commercial Vegetable Production Recommendations Guide.
Tomato stem infected by white hold. Note the fungal growth on the surface of the stem.
White mold of tomato. Note the black sclerotia developing inside the brittle stems.
June 30, 2022 Andy Wyenandt
Recognizing Angular Leaf Spot in Cucurbits
Angular leaf spot is common in New Jersey and the region. It often shows up during cooler, wet weather and isolated rain.
Symptoms of angular leaf spot in cucurbit.
Angular leaf spot of pumpkin. Note leaf ‘shot holes’.
Angular leaf spot will first appear as, small water-soaked lesions which will expand until they reach a larger leaf vein resulting in the angular looking symptoms on leaves. Under heavy disease pressure, the bacteria will infect fruit causing small, water-soaked circular spots. In many cases once weather conditions become dry again, infected tissue in leaves will die and fall out leaving the characteristic ‘shot hole’ symptoms. Control of angular leaf spot begins with the application of labeled rates of fixed copper plus mancozeb to help suppress the spread of the disease until hot, dry weather returns.
June 29, 2022 Kris Holmstrom and Joe Ingerson-Mahar
Vegetable IPM Update 6/29/22
Sweet Corn
Low numbers of European corn borer (ECB) moths remain a sporadic, low component of blacklight trap catches. Feeding in whorl and pre-tassel stage is now less common, as control has been applied to infested plantings and later blocks (now in whorl stage) have avoided most of the egg laying period. Slightly higher adult activity is in scattered pockets around the state (see map below at right). ECB injury over the threshold of 12% of plants infested, while still around, has generally been declining over this past week. We expect feeding wind down over the next week or so as we move into the period between generations.
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 or Vantacor (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 6/29/22 are as follows:
| Bellemeade 1 | Farmingdale 1 | Morristown 1 |
| Blairstown 1 | Georgetown 1 | New Egypt 1 |
| Centerton 1 | Lawrenceville 1 | Princeton 1 |
| Crosswicks 1 | Matawan 1 | Sergeantsville 1 |
