Rutgers NJAES Wine Grape Extension, in association with Penn State Extension Grape and Wine Team, is calling on those who own, operate, or manage a farm or vineyard in the New Jersey region to participate in a survey that aims to track the spread and severity of nymph and adult spotted lanternfly populations during the 2023 season. The data collected will provide insights into the distribution patterns of both nymph and adult SLF within and outside vineyards, enabling growers and researchers to better understand this invasive pest’s potential impact on agriculture in the Mid-Atlantic region. [Read more…]
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.
Subscription is through the general Fruit feed available via EMAIL and RSS.
Managing Blunt-nosed Leafhoppers in Cranberries – 2023
Blunt-nosed leafhoppers (BNLH) are important pests of cranberries in NJ because they vector a phytoplasma that causes false blossom disease. BNLH has one generation a year. It overwinters as eggs, which begin to hatch in early May. The nymphs will go through five instars in about a month. The adults begin to appear by the end of June and are most abundant in mid-July. Numbers of this species start to diminish by the end of July. The adults have a characteristic blunt head and vary from light yellowish-gray to dark brown. Eggs are laid in June-July. Nymphs and adults get their food by sucking the plant juices of the cranberry vines with their piercing-sucking mouthparts. At this time of the year, we are observing early-instar nymphs, mostly 1st instars but also 2nd instars (Figure 1).

Figure 1. Blunt-nosed leafhoppers early-instar nymphs. Photo credit: Paolo Salazar-Mendoza.
Here are some guidelines to consider when managing BNLH in cranberries:
- The most important point in BNLH control is locating the sites of infestation. Monitoring for this insect is accomplished best with an insect sweep net. Nymphs should be monitored before bloom using sweep nets (this time of year). Nymphs before bloom are small (Figure 1); thus, ideally, you may need to freeze the samples (to kill them), and then count the number of nymphs under a microscope or using a magnifying lens.
- To monitor, perform sweep sets of 25 sweeps each. The recommended number of sweep sets is: 1 per 1–10 acres, at least 10 sweep sets per 10–20 acres, and 1 sweep set per 2 acres for more than 20 acres.
- A challenge for managing BNLH is the fact that they vector a phytoplasma that causes false blossom disease. For this reason, it is difficult to establish economic thresholds for this pest because we do not know the proportion of individuals that are infected in the population. Moreover, this proportion can vary depending on the variety. For instance, we have observed higher incidence of infection in the newer varieties even when populations of leafhoppers are low.
- Control measures should be considered based on the number of BNLH relative to previous years, history of insecticide application, and the variety. If BNLH populations are increasing compared to previous years and the beds have not been treated for BNLH for 2-3 years, growers should consider treatment.
- If treatment is necessary, we have a few options to manage BNLH. The best timing for insecticide treatment is before bloom to target the young nymphs. We recommend the use of organophosphates such as Diazinon (diazinon) and Orthene (acephate), carbamates like Sevin (carbaryl), and pyrethroids like Fanfare (bifenthrin) and Danitol (fenpropathrin). Although not proven scientifically, there are claims that Orthene and Sevin can reduce pollinator activity by repelling bees. The neonicotinoids Assail (acetamiprid) and Actara (thiamethoxam) also work well against nymphs, but we do not recommend their use before bloom due to potential negative effects on bees; neonicotinoids are systemic insecticides that can accumulate in the pollen and nectar. Closer (sulfoxaflor) is a new registered insecticide in cranberries with a similar mode of action as the neonicotinoids but that belongs to a different class of insecticides. We have tested Closer in small plot trials at the P.E. Marucci Center and shown that it is effective against BNLH nymphs; however, more data are needed to confirm its efficacy at larger scales in commercial farms.
South Jersey Tree Fruit Twilight Meeting – II
May 31st @ 5 – 7 pm Summit City Orchards: 500 University Blvd. Glassboro, NJ 08028 Pesticide credits applied Category: 1A, PP2, 10 4:45 pm Gather at the Parking lot of the Summit City Winery (above address) 5:00 pm Peach Fruit Thinning - Physiology and Methods Daniel Ward, Extension Specialist, Pomology, Rutgers NJAES. Demonstration of the Peach Fruit Thinning Using the Machine Richard Bannister and Eli Bannister, Richard’s Station. Field Observations from the IPM Program Dave Schmitt, Fruit IPM Program Associate, Rutgers NJAES Summer Disease Control Measures in Orchards Norman Lalancette, Extension Specialist, Tree Fruit Pathology, Rutgers NJAES 7:00 pm Pesticide re-certification credits application and Adjourn Light fare will be provided. Please call Joan Medany jmedany@co.gloucester.nj.us or call 856-224-8030 if you are planning to attend. If an additional assistance is needed, please contact Hemant Gohil at 856-224-8029 prior to the meeting.
Application for Cost-Share Grant Funding for Installation of Deer Fencing on UNPRESERVED Farmland – Out NOW
“The NJDA Deer Fencing Program makes cost-sharing funding available for the installation of deer fencing on unpreserved farms. The program is conducted in accordance with N.J.S.A 4:40-6.1.”
Please click here for the full application, eligibility, and other important information
Timing is important if considering this program. NJDA began accepting applications on 5/15/23.
Early Season Pests of Cranberries, 2023
By now the winter flood is off from most New Jersey cranberry beds. Once the water is removed, the vines will start to initiate bud break. From now until bloom, growers should scout their beds using sweep net sampling for lepidopteran pests (spongy (=gypsy) moth, blackheaded fireworm, spotted fireworm, Sparganothis fruitworm, and cranberry blossomworm), and blunt-nosed leafhoppers (Figure 1).

Figure 1. Spongy moth larva (A); Blackheaded fireworm larva (B); Sparganothis fruitworm larva (C), Spotted fireworm larva (D); Cranberry blossomworm larva (E); Blunt-nosed leafhopper nymph (F). Photo Credits: Elvira de Lange & Dan Schiffhauer.
Spongy moth – Although spongy moth numbers should have dropped compared to the last couple of years, we might see larvae still in places where high infestation occurred, particularly in beds near wooded areas. At this time of the year, the larvae are small (early instars). This insect has one generation a year and overwinters as eggs. Eggs hatch at this time of the year and 1st instars “balloon” on silken threads from infested trees onto nearby cranberry beds. Thus, spongy moths tend to be one of the earliest caterpillars to show up in cranberry beds, usually during the first week of May. The larvae are quite easy to detect by means of sweep net sampling and are easy to control with most of the insecticides at our disposal (see recommendations below).
Blackheaded fireworm – Blackheaded fireworm eggs overwinter on the bed and usually hatch by around mid-May. It is important to catch the first generation, if possible, because the second generation occurs during bloom and is typically much more destructive. Blackheaded fireworm larvae can be detected by sweep net sampling and it is a good idea to look along the edges of beds where vines first begin to grow. Remember: blackheaded fireworm is much easier to control if detected during the early part of the season.
Sparganothis fruitworm – This insect is a serious pest in most cranberry-growing states. It completes 2 generations a year and overwinters as an early-instar larva. The larvae from the 1st generation feed on foliage. In New Jersey, first generation adult moths emerge from mid-June through the first weeks in July; pheromone traps are commonly used to monitor adult flight and population size. The 2nd-generation eggs are laid on cranberry leaves, and larvae will feed on fruit.
Spotted fireworm – This insect overwinters as a 2nd instar larva and completes 2 generations a year. The larvae feed between uprights they have webbed together. First-generation larvae injure the foliage causing it to turn brown as if burned. In New Jersey, 1st-generation adult moths emerge the first week of June, followed by a 2nd-generation adult emergence in early August. Eggs are laid in masses on weedy hosts. The larvae from 2nd-generation adults emerge in mid-August and may feed on fruit. Populations of spotted fireworm are regulated by their natural enemies, particularly Trichogramma wasps that parasitize the eggs.
Cranberry blossomworm – Adults lay their eggs in October in cranberry beds. The eggs overwinter and hatch over a period of several weeks. Early instars can be found during the first week of May. Larvae go through 6 instars to complete their development. Because the first instars feed during the day (and at night), scouting can be done during the daytime using sweep nets to estimate larval abundance. Larvae turn nocturnal during the later instars and thus night sweeping (9 pm – 1 am) is recommended for sampling. Larvae complete their development by June-July. Older instars are very voracious and capable of destroying 100 blossoms within a 3-week period. There is a pre-pupal stage that lasts until the end of August and a pupal stage that lasts until October. Adults emerge from the end of August to the end of October.
Lepidopteran Pests Monitoring and Control – Use sweep netting for monitoring early lepidopteran pests (pre-bloom). A sweep set consists of 25 sweeps and 1 sweep set is recommended per acre (this may vary depending on the size of bogs). The action threshold for false armyworm, blossomworm, other cutworms, and spongy moth (we use a combined threshold from adding all these caterpillars per sweep set) is an average of 4.5 caterpillars in sets of 25 sweeps. For brown and green spanworms is an average of 18 per sweep set. The action threshold for blackheaded fireworm and Sparganothis fruitworm is an average of 1.5 per sweep set. We recommend the use of reduced-risk materials such as the insect growth regulator (IGR) Intrepid, the spinosyn insecticide Delegate, or any of the diamide insecticides Altacor, Exirel or Verdepryn if populations exceed action thresholds. These are reduced-risk, softer insecticides that are very effective against lepidopteran pests. Remember to rotate insecticides with different modes of action to prevent onset of insecticide-resistant pest populations.
Leafhoppers –There is continuing concern among New Jersey cranberry growers of a potential increase in leafhopper populations because of changes in pest management strategies (e.g., adoption of new reduced-risk products and decreased applications of broad-spectrum insecticides). The blunt-nosed leafhopper is of particular concern because this insect can transmit cranberry false blossom disease. This leafhopper has one generation a year. The adults are found in the highest numbers during July, although nymphs or adults may be found from the end of May until October. The eggs are laid in August-September and the overwintered eggs hatch in May or June. The nymphs go through 5 instars to complete their development.
Leafhopper Monitoring and Control: Leafhopper nymphs can be sampled using sweep nets (as described above for lepidopteran pests). Nymphs before bloom are small; thus, you may need to freeze the samples (to kill them), and then count the number of nymphs under a microscope or using a magnifying lens. There is no established threshold based on sweep net counts because it varies depending on the age of beds, the variety, and/or with false blossom incidence. These decisions should be made by comparing current numbers with prior infestation history.
In cases of high numbers of blunt-nosed leafhopper nymphs, we recommend application of a broad-spectrum insecticide, such as Sevin, Diazinon (no aerial applications allowed), Fanfare, or Danitol. Broad-spectrum insecticides will disrupt biological control particularly the natural enemies (predators and parasitoids) of Sparganothis fruitworm, so their use should be restricted only to areas of high leafhopper populations.
South Jersey Wine Grape Twilight Meeting
May 11 (Thu) 4:15 pm Auburn Road Vineyards and Winery 117 Sharptown-Auburn Rd, Pilesgrove, NJ 08098
Pesticide Credits Approved: CORE (1); PP2 (5); 1A (5); 10 (4)
4:30 pm Welcome Remarks and Updates and Social Bird Management – Demonstrations and Interactive session on challenges and successes in bird control Aaron T. Guikema, State Director, USDA – APHIS Wildlife services Potassium Fertilizer Chemistry for Wine Grape Joseph Heckman, Extension Specialist in Soil Fertility, Rutgers NJAES. 2023 Recommendations for Wine Grape Disease Management Peter Oudemans, Extension Specialist, Small Fruit Pathology, Rutgers NJAES Brief Overview of Alternative Options to Paraquat for Postemergence Weed Control. Thierry Besancon, Extension Specialist, Weed Science, Rutgers NJAES Early Season Field Observations from the IPM Program Dave Schmitt, IPM Program Associate, Rutgers NJAES. Spotted Lantern Fly and Other Vineyard Insects Management Anne Nielsen, Tree Fruit Entomologist, Rutgers NJAES 7:30 pm Pesticide re-certification credits Light fare will be provided. Please email Joan Medany at jmedany@co.gloucester.nj.us or call 856-224-8030 if you are planning to attend. This site is accessible to the physically impaired. For the additional assistance, please contact Hemant Gohil at 856-224-8029 before the meeting.