Recent field scouts indicate that damaging populations of tomato fruitworm (TFW) are on the rise. TFW, also known by its more common name the corn earworm, feed directly on tomato fruit. They enter as larva and can cause damage to three or four tomatoes by the time of full maturity. In addition to tomatoes and corn, this insect is also known to feed on tomatillos, peppers, beans, peas, okra, along with other field crops.

Products containing spinosad will help control fruitworm populations but timing is critical as chemical sprays will not impact TFW once they are inside a fruit. Damaged fruit will ripen prematurely. Control of TFW populations is important to minimize secondary pests like mites or aphids. See the New England Vegetable Management Guide for spray options.

Continue to be on the lookout for tobacco and tomato hornworms (tobacco hornworm has a red/pink horn; tomato hornworm has a black or blue horn). Since the leaf-colored hornworms create a decent camouflage, large pellet-like fecal droppings on the plastic mulch under the plant, the defoliation of leaves with only bare stems remaining, or surface feeding scars on green fruit can indicate a nearby hornworm. Caterpillar infestations usually begin in July and may extend through September.

The adult tomato hornworms are large moths, predominantly gray or gray-brown with lighter markings. Their hairy, robust abdomens have yellow spots. They are commonly referred to as sphinx, hawk, or hummingbird moths. The wingspread may reach five inches.

Spot treat areas within a high tunnel using selective insecticides to preserve natural enemies and avoid secondary pest outbreaks (i.e. aphids). Products containing BT (e.g. Dipel and XenTari) are effective and should be rotated for resistance management. These products must be ingested so apply in the evening or early morning before larvae are actively feeding. Adherence will improve with use of approved spreader-sticker.

Humid environments (relative humidity greater than 85%) in combination with tomato plants rapidly growing in to denser plantings (so air circulation is reduced) creates the perfect environment for leaf mold. As a result, leaf mold known by the scientific name Passalora fulva and previously known as Fulvia fulva or Cladosporium fulva, is commonly found in high tunnels. The fungus can cause leaves to yellow and reduce overall yield.

To control leaf mold, it is critical to improve airflow and reduce humidity by venting and pruning. Additional recommendations include:

• Removing infected foliage can slow the spread of disease from leaf to leaf and plant to plant.
• Avoid excessive nitrogen fertilization.
• Remove diseased leaves, place them in a plastic bag, and destroy.
• At the end of the crop cycle, remove and destroy all plant residue.

For the following season, consider using resistant cultivars and certified disease-free seed.

Spray options for greenhouse and high tunnel tomatoes can be found using the New England Vegetable Management Guide.

High humidity or water on leaf surfaces is required for the spread of Stemphylium spore germination and infections. Spots on leaves begin small, light brown, and somewhat circular to irregular in shape. Larger spots may become cracked. Symptoms start to appear within two to five days of infection. It most commonly occurs in high tunnels where higher temperatures and humidity are favorable to disease development.

When selecting which varieties to grow, you can choose tomato varieties with resistance to GLS. Avoid overhead watering as much as possible. Since Stemphylium survives on crop debris as a saprophyte, crop rotation will also help control the spread of the disease along with the sterilization of equipment at the end of the season. Checkout our fact sheet on this!

Verticillium wilt is caused by two species of a soil-borne fungi. It infects eggplants, peppers, tomatoes, cucurbits, and many other crops. A yellowing of lower leaves followed by wilting is the first sign of disease. Lesions have a characteristic V-shaped pattern which is widest at the leaf margin. Symptoms can appear on one side of the plant or on one side of a leaf (a more prevalent symptom in eggplant and tomatoes). When the stems of infected plants are cut lengthwise, the vascular tissue exhibits a brown discoloration.

Verticillium species can persist in the soil for many years in the absence of susceptible plants. Follow a 4-5 year crop rotation with non-solanaceous and non-cucurbit crops to reduce inoculum levels in fields. Include grain crops in the rotation. Control weeds as many weeds are susceptible to Verticillium. Remove and destroy infected plant material after harvest. There are no effective chemical controls, however, some resistant or tolerant eggplant varieties exist.

Extended periods of wetness from fog or dew as nighttime temperatures begin to drop is creating an opportune environment for fungal infections. Alternaria, also referred to as Early Blight of tomato, can cause lesions to form on tomato leaves. They first appear as small brown to black lesions on older foliage, and the tissue surrounding the lesion may become yellow. As the number of lesions grows, the entire leaf can become chlorotic. As the lesions themselves grow, they often develop concentric rings like a bull’s eye or target-spot. In addition to reducing plant vitality, fruits can also be infected by causing them to rot.

One of the most destructive pests of pepper crops growing in Connecticut is bacterial leaf spot (BLS). Bell pepper varieties are particularly vulnerable to this disease, although under favorable conditions, more tolerant varieties of hot or sweet peppers may show varying degrees of susceptibility. The bacteria can be introduced on infected seed or arrive on transplants. It cannot survive in the soil for extended periods, but will live through the winter on the residue of solanaceous crops (especially peppers and tomatoes), on weeds in the nightshade family and on the roots of wheat.

The bacteria may enter leaves through natural openings or abrasions. The presence of water on the leaf surface is important in the infection process and thus, the first symptoms usually occur on the margins or tips of leaves where droplets accumulate. Once inside the plant, the bacteria reproduce rapidly and move through the vascular system, congesting and killing tissue. Symptoms may develop in as little as five days or not show up for six or more weeks.

BLS affects all aboveground parts of the plant. Spots on leaves appear as brown irregular-shaped areas of dead leaf tissue. These spots start out less than 1/4 inch in diameter, grow in size and accumulate in number until the infected leaves drop off. In a severe outbreak, plants will drop 50 to 100% of their foliage, leaving the fruit exposed to the sun and vulnerable to sunscald. Plant stems and branches develop elongated, raised, light-brown cankers. Fruit may develop light-colored, raised, wart-like spots that eventually darken to brown or black.

Good sanitation and preventative practices are essential to minimize the risk of initial infection and reduce the amount of bacteria present early in the disease cycle. If detected in the early stages, when just a few localized plants show symptoms, remove or bury all diseased specimens and symptomless plants for 10 or more feet in all directions. Always work in infected sections of pepper fields last and disinfect machinery after completing the job. Deep plow crop residues after final harvest to speed decomposition of infected tissues.

From 2006 to 2023, the average UV index in July has averaged 9 (on a scale of 13), the highest rating of the year, indicating very high to extreme sun exposure. While pepper crops like the heat, intense sunlight and UV radiation, especially on fruit that isn’t protected by the plant’s leaf canopy, can put the fruit at risk of sunscald. Sunburn is not only damaging to the affected fruit, but it also opens the door to pathogens infecting the entire plant. Other crops that are particularly susceptible to sunscald include tomatoes, cucumbers, eggplant, pumpkins, and squash. Leaves may also be impacted by intense sun. The damage can be identified by bleaching or browning.

Shading is the best protection against sunscald. Be mindful of plants that may have fallen over and add trellising so the fruit can benefit from foliar shade. When selecting varieties, seek out cultivars with thicker plant canopies.

Fruit cracking is a common physiological disorder that affects the appearance and marketability of vegetables, particularly tomatoes, peppers, and eggplants. Radial cracks are deep, lengthwise splits that extend outward from the stem end and are often severe enough to make fruit unmarketable.

Deep cracks not only reduce market quality but also provide entry points for secondary pathogens, increasing the risk of fruit rot. When high temperatures (above 85°F) are followed by low temperatures (below 50°F), this stress can weaken fruit skin elasticity and increase cracking risk. The same can be said for sustained high temperature leading to continual fruit growth that can outpace the skin's ability to stretch. Heirloom varieties and large-fruited tomatoes (such as beefsteaks) are more prone to cracking compared to the hybrids which are often bred for resistance to cracking.

For further reading, check out our fact sheet on this.