Fruit Crops Edition - Cranberry Section

Seasonal updates on diseases, insects, weeds impacting small fruit (blueberry, cranberry, and wine grape). Fruit Pest Alerts are also available via this category feed.
 
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When Plants Get Sick, Pests Thrive: The Unseen Battle in Cranberry Bogs

Our research on how cranberries respond to phytoplasma infection—and its effects on above- and belowground herbivores—was recently featured on the Theobald Smith Society’s website in the article When Plants Get Sick, Pests Thrive: The Unseen Battle in Cranberry Bogs

Phytoplasma infection, which causes false blossom disease in cranberries, is transmitted by the blunt-nosed leafhopper (Limotettix vaccinii). Our findings show that infection increases cranberry susceptibility to herbivores both above and below ground by increasing plant nutrient levels and suppressing plant defenses. This work highlights the complex—and often harmful—interactions among plants, pathogens, and insect herbivores in agricultural ecosystems.

Late June Peach Varieties for New Jersey– New and Standard

The many peach varieties grown in New Jersey were developed in different breeding programs from several peach-growing regions, including the Rutgers Tree Fruit Breeding program. Recent evaluations have examined the known characteristics and challenges growers face in growing these varieties. These are important for making planting, thinning, harvesting, post-harvest handling, and marketing-related decisions. Understanding these differences is important for selecting varieties or replacing existing ones.

Desiree is a very attractive yellow-fleshed, clingstone peach variety, ripening during the last week of June. The fruit is beautiful and medium to moderately large, which is impressive for the early-season variety. The flesh is firm with a very sweet and tangy flavor. The tree is vigorous, and its leaves have low susceptibility to bacterial spot. The fruit is also having low susceptibility to Bacterial Spot. [Read more…]

Sparganothis Fruitworm Degree-Day Update: As of June 23, 2025

By: James Shope and Cesar Rodriguez-Saona

As of June 23, Sparganothis fruitworm has accumulated 1,225 degree-days (DD) since the April 15 biofix, based on our degree-day model. This suggests that flight activity has surpassed 90%, with peak flight likely occurring around June 19, 2025. The model reflects average conditions across multiple beds, so some variation may occur depending on the variety. We will continue to provide updates as the season progresses. If needed, an insecticide application is recommended two weeks after peak trap catches—around July 3.

High Temperatures Predicted this Coming Week – Ways to Prevent Heat Stress

OSHA Safe + Sound Header for Heat Illness Prevention

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:

  • Limit exposure time. Schedule as many physical work activities as practical for the coolest part of the day (early morning or late afternoon). Employ additional help or increase mechanical assistance, if possible, to lighten individual workloads.
  • Minimize heat exposure by taking advantage of natural or mechanical ventilation (increased air velocities up to 5 mph increase the rate of evaporation and thus the rate of heat loss from the body) and heat shields/shade when applicable.
  • Take rest breaks at frequent, regular intervals, preferably in a cool environment sheltered from direct sunlight. Anyone experiencing extreme heat discomfort should rest immediately and be provided with first aid for heat stress.
  • Wear clothing that is permeable to air and loose fitting. Generally, less clothing is desirable in hot environments, except when the air temperature is greater than 95°F or a person is standing next to a radiant heat source. In these cases, covering exposed skin can reduce the risk of heat stress.
  • A buddy system may also be helpful. It depends on a fellow worker’s ability to spot the early signs of heat stress, such as irritability, confusion, or clumsiness. A ready means of cooling should be available in work areas where heat illness might occur.

Videos on Blunt-nosed Leafhoppers and False Blossom Disease

In collaboration with Washington State University and the Western IPM Center, we produced three YouTube videos focusing on blunt-nosed leafhoppers and false blossom disease.

Ben-Zvi, Y., Rodriguez-Saona, C., Kraft, L., Ben-Zvi, E. Blunt-nosed leafhoppers and cranberry false blossom disease: I. Biology and symptoms. Western IPM, extension video series. https://www.youtube.com/watch?v=nEujE6nNF58

Ben-Zvi, Y., Rodriguez-Saona, C., Kraft, L., Ben-Zvi, E. Blunt-nosed leafhoppers and cranberry false blossom disease: II. Grower interviews. Western IPM, extension video series. https://www.youtube.com/watch?v=Lpvwl9QzIEM

Ben-Zvi, Y., Rodriguez-Saona, C., Kraft, L., Ben-Zvi, E. Blunt-nosed leafhoppers and cranberry false blossom disease: III. Current research. Western IPM, extension video series. https://www.youtube.com/watch?v=9vh-eKUt_5U

Deer Damage Control in the Vineyard

New Jersey’s high deer population significantly threatens vineyards, particularly those near wooded areas. Deer are a pest, especially on young vines and in the early growing season when food sources are scarce, and tender shoots are emerging. If the vineyard is close to the deer population, management is needed for the long-term productivity of the vineyards.

Identifying the deer damage: Deer browse on leaves and tender shoots using the lower front teeth. Deer do not have upper incisors, so the leaves browsed by deer have a rough, torn, and shredded appearance but no tooth marks (Figure 1). This can cause substantial crop loss and even compromise the health of the vines, specifically if the same vine is damaged over the years (Figure 1). Fortunately, secondary buds of grapevines can grow and produce replacement shoots when the actively growing shoot tip from the primary bud is damaged. A new shoot from a basal bud may not be as productive, however, it will ensure new vegetative growth, sustaining the canopy of the grapevine. [Read more…]