Rutgers Cooperative Extension
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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WVU Extension and other colleagues are trying to understand how we can better help you with your Agritourism Marketing. It will tremendously help us to help you in the future.
Please take a few minutes (at most 5 minutes) to answer the questions here: https://s.uconn.edu/agritourism-marketing
Calling all commercial basil growers, researchers, home gardeners, and basil enthusiasts!
Our team at Rutgers University, UMass Amherst, Bar-Ilan University, and University of Florida
are asking for your help! Basil production is still threatened by the devastating Basil Downy
Mildew disease and current methods of prevention and resistance are wavering. It appears that
the pathogen is evolving rapidly, and we need your help to understand this phenomenon. We are
asking anyone who observes basil downy mildew on their plants to send infected leaf samples to
our researchers listed below and to report their infection to the following website:
https://basil.agpestmonitor.org/. These samples will be used to better understand the existing
pathogen populations and help drive solutions towards the downy mildew problem. This problem
cannot be solved alone, and we thank you!
Shipping Instructions:
Please collect as many infected leaves showing sporulation (or yellowing) as possible and wrap
in a dry paper towel before placing inside a sandwich bag. Seal the sandwich bag partially
(leaving about a quarter open) before placing in an envelope addressed with the information
below:
Rutgers University Mailing Information:
B.A.S.I.L.
Foran Hall, Rm 392
59 Dudley Rd
New Brunswick, NJ 08901
Please address any questions or concerns you may have to Robert Mattera III
(robert.mattera@rutgers.edu)
Greetings from the Veg IPM team!
Sweet Corn
With the hot weather, we’re starting to see sweet corn really coming along. Some plantings of sweet corn are silking (especially in the south), so it’s time to think about corn earworm management. Moth captures in the Southern part of the state (see map) are indicating that 4 and even 3 day intervals are necessary in some areas. 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.
Cole Crops
Flea beetle surrounded by feeding damage. Picture by Maria Cramer.
Flea beetle activity seems to be slowing down some, but they are still active in various cole crops. This year, they have been especially prevalent in lacinato kale, Napa cabbage and bok choy. Young plants are especially vulnerable to attack from flea beetles. The treatment threshold for flea beetles in heading cole crops is 50% infestation.
Left: Diamondback moth caterpillar, showing characteristic tapering at each end. Right: Imported cabbageworm caterpillar showing characteristic fuzziness. Pictures by Maria Cramer.
We’re still seeing caterpillar activity in cabbage and other cole crops. Treatment thresholds vary between crops and growth stage, but for heading cole crops between early vegetative and cupping, the treatment threshold is 30%. At this stage, 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 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.
Tomatoes
In high tunnels and field plantings of tomatoes, we’re seeing limited aphid, thrips, and spider mite activity. If dealing with primarily aphids, products such as Beleaf (IRAC 29) are recommended, especially if plants have reached the flowering stage. We have seen aphid populations decline over the last couple of weeks without spray, probably due to natural enemies predation. For thrips, Entrust, Radiant (IRAC 5) and Torac (IRAC 21A) can be used. For spider mites, Nealta (IRAC 25) is an effective material that is more friendly to beneficial insects, but Portal (IRAC 21A) and other materials can be used to manage populations. We’ve seen very few Colorado potato beetles (CPB) in tomatoes, so while no controls are needed yet, we’ll keep an eye out for increasing populations.
Eggplants
In eggplants we have seen some damaging populations of CPB. For plants under 6 inches, 2 small/1 large larvae per plant is the threshold, while for plants taller than 6 inches, the threshold is 4 small/2 large larvae per plant. Adults are hard to kill, so sprays should target the larvae, with younger/smaller larvae being more vulnerable than older larvae. CPB has resistance to many classes of insecticides and is notorious for quickly developing resistance to new ones, so plan to rotate IRAC groups if you’ve already treated or need to treat more than once. If you haven’t used a neonic (IRAC 4) at planting or in the drip, you can use a foliar neonic like Assail or a spinosyn like Entrust or Radiant (IRAC 5). Avoid IRAC 5 groups if you’ve already used a neonic, because there is risk of cross resistance. Diamide products like Coragen and Exirel (IRAC 28), Rimon (IRAC 15), and Torac (IRAC 21A) should all give good control.
Left: Colorado potato beetle larvae and feeding damage on an eggplant leaf. Right: Adult Colorado potato beetle. Photos by Maria Cramer.
Diseases
We’ve detected bacterial diseases of tomatoes and peppers on a few farms in the central and northern parts of the state (see photos below). Copper may help mitigate symptoms, but some strains have developed resistance due to continued copper use. Other products that may help include Actigard and Quintec. Otherwise, properly managing nutrients and growing conditions for the plant will be crucial for reducing the severity of this disease.
Bacterial leaf spot on tomato. Photo by Amanda Quadrel
Bacterial leaf spot on pepper. Photo by Amanda Quadrel.
Please consult the Mid-Atlantic Commercial Vegetable Production Guide for a more comprehensive list of materials that are labeled for specific crops and pests. As always, be sure to follow label rates and application instructions.
Authors: Amanda Quadrel (Northern NJ Veg IPM coordinator) and Maria Cramer (Southern NJ Veg IPM coordinator)
Heat exposure for agricultural laborers should be a consideration when working outside and even in non-airconditioned buildings. When a person’s ability to adapt to heat stress is exceeded, exposure can lead to reduced productivity, mistakes in job performance, increased workplace incidents, and/or heat-related illnesses. Each person’s heat tolerance varies and several factors including type of physical activity, fitness level, underlying health issues, temperature, sun exposure, air movement (wind), and humidity can dramatically impact the potential for heat stress. To determine the level of heat risk, employers should consider the job, the environment, and the worker.
Evaluate the Risk of Heat Stress:
Monitoring the environmental conditions during work times to make management decisions for workers is an important part of preventing heat-related illnesses. Temperature is not the only factor in implementing heat stress management. Humidity is another important consideration. The heat index is a measure of how hot it feels when the relative humidity is factored in with the actual air temperature.
An environmental heat assessment should account for the following factors: air temperature, humidity, radiant heat from sunlight or other artificial heat sources, and air movement. OSHA recommends the use of wet bulb globe temperature (WBGT) monitor to measure workplace environmental heat. OSHA provides this link to calculate the WBGT for a specific location. There is also a NIOSH/OSHA Heat App for Android and iPhone devices that uses the Heat Index as a screening tool.
Management Suggestions for Enhancing Heat Tolerance:
Acclimatization (to heat) is a process of adaptation that involves a stepwise adjustment to heat over a week or sometimes longer. An acceptable schedule for achieving acclimatization is to limit occupational heat exposure to one-third of the workday during the first and second days, one-half of the workday during the third and fourth days, and two-thirds of the workday during the fifth and sixth days. The acclimatization procedure should be repeated if a person misses workdays after days off due to illness, vacation, or other reasons for missing one week or more of job duties.
Fluid replacement:
Provide adequate drinking water for all employees. Recommend to employees they drink plenty of water before work shifts, during work, and after work. Simply relying on feeling thirsty will not ensure adequate hydration. To replace the four to eight quarts of sweat that may be produced in hot environments, people require one-half to one cup of water every 20 minutes of the workday. Potable drinking water kept at a temperature of 59°F or less is recommended.
Physical Fitness: Physical fitness is extremely important. The rate of acclimatization is a function of the individual’s physical fitness. The unfit worker takes 50 percent longer to acclimate than one who is fit.
Increasing Safe Work Practices:
To find management and guidance tools for determining whether to implement heat stress management plans refer to the CDC documents on Heat Stress and Work/Rest Schedules.
The following list of management options should be considered to prevent heat stress for workers:
Greetings from the Veg IPM team! The program welcomes Martina Lavender and Coco Lin as the first two scouts of the season, servicing North and Central Jersey respectively.
Sweet Corn
We’ve put out corn earworm pheromone traps throughout the state. While silking corn is the main target of CEW activity, we set the traps early to detect overwintering moths. So far, we haven’t spotted any serious corn pests through visual inspection.
Cole Crops
Flea beetle surrounded by feeding damage. Picture by Maria Cramer.
Flea beetle remain active in various cole crops. This year, they have been especially prevalent in lacinato kale, Napa cabbage and bok choy. Young plants are especially vulnerable to attack from flea beetles. The treatment threshold for flea beetles in heading cole crops is 50% infestation.
Left: Diamondback moth caterpillar, showing characteristic tapering at each end. Right: Imported cabbageworm caterpillar showing characteristic fuzziness. Pictures by Maria Cramer.
We’re seeing caterpillar activity (imported cabbageworm in the North and diamondback moth in the South) in cabbage and other cole crops. Treatment thresholds vary between crops and growth stage, but for heading cole crops between early vegetative and cupping, the treatment threshold is 30%. At this stage, 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 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.
Tomatoes
In high tunnels and the first field plantings of tomatoes, we’re seeing limited aphid, thrips, and spider mite activity. If dealing with primarily aphids, products such as Beleaf (IRAC 29) are recommended, especially if plants have reached the flowering stage. We have seen aphid populations decline over the last couple of weeks without spray, probably due to lady beetle predation and parasitism from wasps. For thrips, Entrust, Radiant (IRAC 5) and Torac (IRAC 21A) can be used. For spider mites, Nealta (IRAC 25) is an effective material that is more friendly to beneficial insects, but Portal (IRAC 21A) and other materials can be used to manage populations. We’ve seen very few Colorado potato beetles, so while no controls are needed yet, we’ll keep an eye out for increasing populations.
Colorado potato beetle adult in tomato
Diseases
With little break in the rainy weather, we’re seeing plants stressed by flooding and some bacterial and fungal diseases popping up in tomatoes, peppers, and cole crops. If you’re seeing disease symptoms and need a diagnosis, samples can be sent to Rutgers Plant Diagnostic Laboratory.
We’ve detected bacterial leaf spot of tomatoes and peppers on a few farms in the central and northern parts of the state (see photos below). Copper may help mitigate symptoms, but some strains have developed resistance due to continued copper use. Other products that may help include Actigard and Quintec. Otherwise, properly managing nutrients and growing conditions for the plant will be crucial for reducing the severity of this disease.
Bacterial leaf spot on tomato
Bacterial leaf spot on pepper
Despite the rain, we also saw some rhizoctonia in cole crops, which shows up when transplant plugs dry out. For more information on this disease, check out the recent update in the PPA.
Please consult the Mid-Atlantic Commercial Vegetable Production Guide for a more comprehensive list of materials that are labeled for specific crops and pests. As always, be sure to follow label rates and application instructions.
Authors: Amanda Quadrel (Northern NJ Veg IPM coordinator) and Maria Cramer (Southern NJ Veg IPM coordinator)
Tomato spotted wilt virus (TSWV) has caused significant problems for some fresh-market tomato and pepper growers in New Jersey the past few growing seasons. TSWV has already been detected in tomato this growing season. Although TSWV is not uncommon, economic losses these past few years have been extensive on some farms.
TSWV is vectored by various species of thrips, a common vegetable insect pest that seems to be on the incline and very difficult to control in vegetable production throughout the state. The most important vector of TSWV is the western flower thrips, Frankliniella occidentalis. It’s mode of transmission is persistent propagative, meaning that thrips nymphs have to feed on an infected plant, whereby followed by a short incubation period (lasting from hours to days), the virus is then persistently transmitted throughout the rest of the insect’s life span.
TSWV cannot be passed from infected females to eggs; and TSWV is not transmitted in seed.
The western flower thrips and TSWV both have a wide host range! Western flower thrips host range includes: tomato, pepper, onion, celery, cucumber, lettuce, potato, basil, strawberry; a wide range of herbaceous ornamentals (e.g., impatiens, geranium, marigold, petunia, dahlia, gerbera daisy, carnation) as well as many common weeds (e.g., pigweed, chickweed, lambs quarter, thistle, galinsoga). TSMV can infect over 1,000 plant species from more than 90 plant families.
In California and other tomato production regions, resistance-breaking (RB) strains (C118Y, C118F, T120N) of TSWV have recently been discovered that can overcome the single gene resistance (Sw-5b) bred into widely-grown processing and fresh-market tomato varieties. Recent research in TX has also shown that RB TSWV strains may increase western flower thrips fitness (ability to reproduce) by prolonging the adult period and increasing fecundity (i.e., a measure of an insect’s reproductive success, often expressed as the number of eggs or offspring produced by an insect) compared to non-RB and non-viruliferous controls. Unfortunately, the breakdown of genetic resistance along with the potential increase in TSWV-infected thrips reproduction rates, may lead to significant problems in thrips and TSWV control in New Jersey and elsewhere.
Recent work in Texas has shown that RB-TSWV can break resistance (conferred by the commonly deployed TSW-mediated single gene resistance) in TSWV-resistant pepper (Capsicum annuum) with varying levels of symptom development in both resistant and susceptible cultivars; with none being completely immune.
In October 2022, samples of a TSWV-infected fresh market tomato variety with Sw-5b resistance were collected in southern New Jersey and sent for analysis. Results determined that RB (C118Y) TSWV was present in the state; and the strain found in New Jersey was similar to the RB TSWV found in fresh-market tomato from Mexico and processing tomato in California suggesting a high potential for its widespread movement.
So, where do we go from here? Based on the isolated reports of TSWV and RB-TSWV being found on on a few farms the past few growing seasons, it does not appear that RB TSWV is currently widespread throughout the state. However, this may likely change and all growers need to be diligent.
All vegetable growers, those who produce their own transplants or bring them in, need to carefully evaluate their thrips monitoring and mitigation programs this winter.
Growers should continue to utilize TSWV-resistant tomato and pepper varieties realizing the effectiveness of those in limiting TSWV is becoming compromised. All growers need to continue to follow best management practices (such as those listed above) and pay careful attention to current weaknesses in their production practices and thrips control programs and adjust their management practices heading into 2025 growing season.
by: Andy Wyenandt and Kris Holmstrom
References:
Macedo MA, Melgarejo T, Cespedes M, Rojas M, Lazicki P, Turini T, et al. (2024) An all-out assault on a dominant resistance gene: Local emergence, establishment, and spread of strains of tomato spotted wilt orthotospovirus (TSWV) that overcome Sw-5b-mediated resistance in fresh market and processing tomatoes in California. PLoS ONE 19(7): e0305402.
Tomato spotted wilt virus on pepper and tomato. Inga Meadows and Andy Cooper, NCSU 2024
Gautam et al., 2022. First report of a resistance-breaking strain of tomato spotted wilt orthotospovirus infecting Capsicum annuum with Tsw resistance gene in Texas. Plant Dis. 107:1958.
