Botrytis, or gray mold, caused by the fungus, Botrytis cinerea, can cause significant losses in high tunnel and greenhouse tomato production if not controlled properly. The pathogen can rapidly spread during periods when structures are closed and when relative humidity remains high for long periods of time. This often occurs when outside weather remains cool and damp while heating is needed. Gray mold is favored by temperatures from 64° to 75°F and requires only high humidity (not leaf wetness) to become established. The pathogen has a large host range and once established in an enclosed structure it can be very difficult to control (UMASS). The fungus can survive/overwinter as mycelia or sclerotia in plant debris and in organic soil matter (NCSU).
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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Identifying and controlling Botrytis in high tunnel and greenhouse tomato production
Controlling Anthracnose and Alternaria Leaf Blights in Cucurbit Crops
Anthracnose and Alternaria leaf blight can become problematic in cucurbit crops during long periods of wet, humid weather. Both can cause significant losses if not controlled properly. With the production season in full swing, now is a good time to review a few of these important diseases. [Read more…]
Diagnosing leaf diseases in sweet (and field) corn in the mid-Atlantic region
Dr. Alyssa Koehler, Field Crops Pathologist from the University of Delaware, recently posted a great diagnostic guide for important fungal leaf diseases in corn. Click here for more information. If you want to follow what is going on in Delaware you can sign up for their Weekly Crop Update by clicking here.
Diagnosing important diseases in Cucurbit crops – Reference Guide
The following images consist of important diseases in cucurbit crops. These images can be used as a quick reference for diagnosing important fungal and bacterial pathogens. For best results, please turn your device (i.e., cell phone) sideways. For information on commercial control recommendations, please visit the cucurbit sections of the 2024/2025 Mid-Atlantic Commercial Vegetable Production Guide.
| Cucurbit powdery mildew (CPM) | Cucurbit powdery mildew | CPM on infected pumpkin stem |
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| Cucurbit downy mildew (CDM) | CDM sporulating on underside of infected cucumber leaf | CDM sporulating on underside of infected cucumber leaf with 10x hand |
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| Anthracnose on cucumber | Anthracnose lesion on infected leaf vein | Anthracnose-infected cucumber fruit |
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| Plectosporium blight on infected stem | Plectosporium lesions on infected vines | Plectosporium lesions on infected pumpkin fruit |
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| Phytophthora blight symptoms | Phytophthora-infected squash | Phytophthora-infected watermelon field |
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| Phytophthora-infected pumpkin | Phytophthora-infected squash fruit | Phytophthora-infected watermelon fruit |
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| Mosaic virus symptoms on leaves of infected pumpkin plant | Pumpkin fruit infected with mosaic virus | Virus infected squash fruit |
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| Fusarium fruit rot of pumpkin | White mold on infected fruit | Gummy stem blight |
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| Choanephora-infected fruit | Choanephora spores in infected pumpkin fruit | Choanephora infecting giant pumpkin fruit |
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| Bacterial wilt infected plant | Symptoms of bacterial canker infected stem | Damage done by cucumber beetle feeding |
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| Angular leaf spot | Shot holes in pumpkin leaves caused by Angular leaf spot in pumpkin | Mature pumpkin fruit with sunscald injury due to the loss of plant canopy |
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Andy Wyenandt and Kris Holmstrom
Veg IPM update 7/18/25
Greetings from the Veg IPM team!
Sweet Corn
Corn earworm moth captures are increasing, leading to 3- or 4-day spray intervals being needed throughout the state. When temperatures are high (>85 degrees F), shorten the spray interval by one day. Rotation is important for avoiding resistance, and there are four IRAC groups that are registered in silking sweet corn: 1 (carbamates), 3 (pyrethroids), 5 (spinosyns), and 28 (diamides). Corn earworm is at least partly resistant to several pyrethroids, so a spray program should not rely solely on pyrethroids, although they can be useful in tank-mixes or as pre-mixed products, such as Besiege or Elevest (Group 28 + Group 3). For detailed information about resistance and potential spray programs, the University of Delaware has an excellent resource on corn earworm management.
Spray intervals based on nightly pheromone moth captures for the southern part of New Jersey. Note that not all locations in the IPM program are currently trapping. This map is based on the following thresholds: 0 moths = 6-7 day schedule, 1 moth = 5 day spray schedule, 2-20 moths = 4 day spray schedule, 20+ moths = 3 day spray schedule.
Fall armyworm (FAW) infestations are beginning to pick up in some locations. Young larvae will cause damage known as “window paning”, in which the top surface of the leaf is eaten away, leaving behind thin, white, membranous-looking scratch marks. As the larvae age, these feeding marks become more ragged (A). The damage can look somewhat similar to European corn borer feeding, but FAW damage will be more severe and will lead down into the whorl. The caterpillars will have a dark head capsule with a distinct, inverted Y-shaped suture (B). We recommend using products other than diamides (IRAC Group 28) when treating whorl-stage infestations, as diamides are important to save for silk protection. Effective products include Lannate (Group 1A), Radiant (Group 5), Intrepid (Group 18), Intrepid Edge (5+18), and Avaunt (Group 22). Note that Avaunt can only be used through tassel push.
Fall armyworm damage (A) and larva (B). Note the distinct suture on the head, which will differentiate FAW from other caterpillar pests of corn. Photos by Amanda Quadrel
Tomatoes
Throughout New Jersey we’re continuing to see high thrips counts both in tunnels and in the field, although numbers have been higher in tunnels. We consider more than 5 thrips on 10 leaves a high count. Other guides suggest 3-5 thrips per flower or the presence of stippling damage on fruit to be a treatment threshold. Thrips management is especially important because of their ability to vector tomato spotted wilt virus (TSWV), a growing concern in New Jersey where we have resistance-breaking strains. We have seen several locations in our scouting program with small outbreaks of TSWV (in both peppers and tomatoes) so far. Scouting and roguing out these plants while continuing to manage thrips should help prevent serious losses. Additionally, follow best management practices for reducing TSWV risk throughout the season.
A) TSWV on a tomato leaf. Note the circle-shaped brown lesions. B) TSWV on a pepper plant. Note the distortion of leaves all over the plant as well as the yellow wavy lines and circles visible on leaves. Photos by Maria Cramer.
Caterpillar pests have begun showing up in throughout the state. We’ve seen some fruit damage, and tomato fruitworm (AKA corn earworm), beet armyworm, and hornworms on plants and fruit. There are no reliable thresholds for determining when to spray for these caterpillar pests, however scouting and consulting the corn earworm pressure map for the state will help give a sense of risk to the crop. When corn earworm pressure indicates a 3 or 4 day spray interval in corn (2-20 moths per night) as is currently the case in much of the state, tomatoes should be scouted weekly for feeding damage. Pyrethroid resistance is widespread in tomato fruitworm/corn earworm and beet armyworm, so other classes of insecticides should be used if management is needed.
With consistent hot temperatures, we’re seeing more spider mites in tomato plantings. Spider mites tend to be worse in hot, dry conditions, and especially thrive in tunnels. Their populations often dramatically increase following broad-spectrum insecticides, which reduce their natural enemies. The first sign of their presence is often light-colored stippling seen on the top surface of tomato leaves. The mites causing this damage are usually found on the undersides of leaves. For spider mites, Nealta (IRAC 25) and Oberon (IRAC 23) are effective materials that are more friendly to beneficial insects, but Portal (IRAC 21A) and other materials can also be used to manage populations.
Spider mite stippling visible when looking at tomato leaves from above. The spider mites are found on the undersides of the leaves. Photo by Maria Cramer.
Peppers
In terms of most insect pests, peppers have been looking very good. We have seen aphids, spider mites, and thrips at low levels so far, however it’s important to keep in mind that thrips can transmit TSWV to peppers as well, and so monitoring and staying on top of thrips populations is crucial. As with tomatoes, finding and roguing out infected plants is important as well. See previous section for an example of TSWV symptoms in peppers.
As a reminder, in June we saw several pepper weevils on pepper weevil traps in Cumberland and Salem Counties. Read more about pepper weevil biology and management here. If you think you may have pepper weevil on your farm or are interested in monitoring, please contact Maria Cramer.
Cole Crops
We are no longer seeing many flea beetles in cole crops, but we continue to see caterpillar activity. Treatment thresholds vary between crops and growth stage, but for heading cole crops between early vegetative and cupping, the treatment threshold is 30%. As heads form, the treatment threshold goes down to just 5% infestation. Sprayable Bt products (IRAC 11A) such as Dipel, Xentari, or Javelin can be effective on young imported cabbage worm caterpillars. Other materials approved for caterpillar control include Entrust/Radiant (IRAC 5), Proclaim (IRAC 6), Torac (IRAC 21A), and Exirel (IRAC 28). Diamondback moth (the primary caterpillar found in southern NJ) has resistance to many insecticide groups, and pyrethroids (IRAC 3A) are not effective for their management. For Bt products and contact insecticides, coverage on the undersides the leaves is essential.
Left: Diamondback moth caterpillar, showing characteristic tapering at each end. Right: Imported cabbageworm caterpillar showing characteristic fuzziness. Pictures by Maria Cramer.
Pumpkins and Other Cucurbits
Cucurbit downy mildew was first reported on 7/11/25 on cucumbers in central NJ and has been found on cucumbers and cantaloupe at the Snyder Research Farm in Pittstown. Growers should be applying protectants on cucumbers and cantaloupes for cucurbit downy mildew at this time. As of this post, we haven’t found any instances of the disease on pumpkins, squash, or watermelon. For information on how to build an effective cucurbit down mildew control program, please reference this post by Dr. Andy Wyenandt and consult the Mid-Atlantic Production Guide for additional materials that can be used.
Cucurbit downy mildew symptoms on the upper surface (A) and underside (B) of cucumber leaves and symptoms on cantaloupe (C). Photos by Amanda Quadrel
In pumpkins, we’ve seen few insect issues, although adult squash bugs and egg masses are starting to appear. Consider treating for squash bug if you see more than one egg mass or group of nymphs per plant (see photos below).
Squash bug eggs (A), newly hatched nymphs (B), and an adult (C). Photos by Amanda Quadrel
We have also seen isolated cases of anthracnose, bacterial wilt, plectosporium, and phythophthora root rot. A preventative diseases management plan based on recommendations from the Mid-Atlantic Production Guide is important for suppressing many of these diseases. If you suspect diseases in your pumpkins (or other cucurbits), reference the “Diagnosing important diseases in Cucurbit crops” guide or send/bring samples to Rutger’s Plant Diagnostic Lab.
As always, please consult the Mid-Atlantic Commercial Vegetable Production Guide for a comprehensive list of materials that are labeled for specific crops and pests. As always, be sure to follow label rates and application instructions.
The Vegetable IPM Program wishes to thank the following Field Technicians, without whom much of the information presented weekly here would not be available:
Southern team: Renee Carter, Kris Szymanski, and Nick Vergara
Northern team: Martina Lavender, Coco Lin, and Cassandra Dougherty
Early July Peach Varieties – Sentry, Glenglo, Ruby Prince, Garnet Beauty, and Sugar May
Warmer temperatures and periodic rains in the last few weeks helped early July peach varieties achieve a bigger size. There are excellent peach varieties throughout the harvest season; however, each has a few challenges, and understanding the overall tree and fruit characteristics can help make thinning, harvest, disease management, and post-harvest decisions. The Newer varieties were also compared against standard varieties. Understanding these differences is essential for selecting new varieties or replacing existing ones. Note that these varieties were evaluated in southern New Jersey; as a result, the harvest dates could be a few days later for the Central and Northern New Jersey orchards.
Sentry: It’s a medium-large to large, red over green-yellow ground-colored peach that ripens during the first week of July. The flesh is moderately firm, very sweet, and mildly tangy (Total Soluble Solids (TSS) 11.32 Brix and Titratable Acidity (TA) 2.08 g/l). It is one of the sweeter varieties in this harvest window. In general, the TSS greater than 11 Brix is considered very sweet. It can get bigger up to 3 inches in diameter, however, at the cost of firmness. It has low susceptibility to the bacterial spot.
Challenges: The main challenge is that fruit has a variable cropping record, but growers prefer it because of its size and taste. Also, a green-yellow background color may give the impression of unripe fruit. Some growers have noticed that older trees of Sentry produced unevenly ripened fruit where one end of the tip was softer while the other end was much firmer. Bigger fruits tend to split. The general recommendation is to avoid letting fruit get bigger than 2 ¾ inches till the Redhaven season.
Glenglo: It’s an attractive yellow-fleshed peach that gets harvested a few days after ‘Sentry’. In some years, it gets harvested before Sentry or overlaps with Sentry. The fruit is medium-large in size, sweet, acidic, and mildly tangy (TSS 11 Brix; and TA 2.5 g/l). It has low susceptibility to bacterial Spot. The cold-hardiness is better than Sentry’s. Glenglo is comparable to Sentry; however, it does not have the problem of uneven ripening. It is considered worthy of replacing “Sentry.
Ruby Prince: It’s a medium-large, globose, and attractive semi-clingstone yellow-fleshed peach variety that ripens a few days after Sentry and Glenglo. The flesh is moderately firm with a sweet and mildly tangy flavor. The scarlet-red over yellow skin color and uniform shape of fruit makes it very attractive variety. It is a worthy replacement of ‘Sentry’. The flesh has greater traces of red. Fruit size is medium to large and uniform.
Garnet Beauty is a sport of Redhaven, ripening about 12-14 days earlier. Yellow-fleshed, clingstone, medium-sized peach, relatively hardy with 40-60% red blush. Fruit is high quality, firm, and freestone when fully ripe. The fruit has a prominent suture groove. The tree is vigorous and productive. The flavor is not great compared to other varieties this season.
Other yellow-fleshed peach varieties: Flaming Fury PF7 is a medium to medium-large, semi-freestone yellow-fleshed peach that ripens during the Glenglo season. This is a good-yielding peach variety; however, most other varieties have better sizes.
White-fleshed Peach Varieties.
Sugar May is a firm, white-fleshed, clingstone peach ripening around July 7. dark red to purplish red skin color. The flavor is good, but acidic. The tree is vigorous and productive but susceptible to bacterial spot.
Challenges: For the white fleshed peach, it is a little too acidic, and some consumers’ expects white peaches in general to be very sweet and sub-acid. Skin is dark red, so one must bite to determine if it has ripened. The core stays greenish-yellow. As seen in the photo, the first superficial (right) bite has cream flesh; however, the slightly deeper (left) bite has greenish flesh. Also, it is moderately susceptible to bacterial spot.
