Blunt-nosed leafhoppers (BNLH) continue to be an increasing threat to cranberries in NJ. BNLH has one generation a year. It overwinters as eggs, which begin to hatch in early May. The nymphs (Picture 1) 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. This direct injury is, however, not noticeable. They are most important as vectors of false blossom disease. Infected uprights produce sterile flowers (do not produce berries). Branching is stimulated in infected plants resulting in a witches’ broom. Foliage on infected plants might redden prematurely and fall.

Picture 1. Blunt-nosed leafhopper nymph. Photo by Elvira de Lange.

Here are some guidelines to consider when managing BNLH in cranberries:

1. 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; 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.
2. 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.
3. 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.
4. Although this needs to be tested, based on experience, I came up with the following tentative treatment thresholds:

– An average of 20 nymphs per sweep set if it is a new variety bed, bed with young plantings, and/or a bed that has a recent history of false blossom.

– An average of 40 nymphs per sweep set if it is an older bed and older variety with no previous history of false blossom.

5. 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.
6. If growers have treated for BNLH in the previous year and populations are low (average of less than 10-20 BNLH per sweep set), there is no need to treat again. Keep a record of the BNLH numbers and check those same beds again the following year to see if the numbers have increased.
7. In most cases, there is no need to apply broad-spectrum insecticides (organophosphates, carbamates, pyrethroids) to control BNLH for two or more consecutive years. These insecticides will disrupt the biological control of other pests such as Sparganothis fruitworm and therefore cause increases in insecticide use.
8. 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, i.e., at this time of the year. 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 the use of neonicotinoids 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.

Like last year, we have reports of high numbers of spongy (= gypsy) moth larvae in cranberry beds near wooded areas. This is the same time that we observed them last year. Looking at the weather conditions, it is expected to rain and be windy and cold on Friday 06 May (tomorrow) and Saturday 07 May. At this moment, the larvae are small (early instars) and because it will be cold in the next few days, I don’t expect them to grow, or be active, that much. Thus, I think it is best to wait until early next week to spray to control them, if needed. The weather looks better next week.

Biology. Spongy moth has one generation a year. It overwinters as eggs. Eggs hatch at this time of the year (we should have already passed peak egg hatch). First 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. Observed larvae are mostly early instars and will feed on the terminal buds. Although less common, it is also possible that eggs overwintered on the bog floor and that older larvae will crawl later in the season onto beds from surrounding trees.

Scouting and Control – Spongy moth 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. The action threshold for spongy moth is an average of 4.5 larvae in sets of 25 sweeps. We recommend the use of Intrepid, Delegate, Altacor, Exirel, or Verdepryn if populations exceed action thresholds. These are reduced-risk insecticides that are very effective against lepidopteran pests.

This article has been adapted from an article written by Dr. Christelle Guédot, University of Wisconsin-Madison, and published in the Cranberry Crop Management Journal – Volume 35, Issue 1

Fanfare is a not a new insecticide, having been first registered with EPA (Environmental Protection Agency) in 1985, but it is new to the cranberry industry. Fanfare is the second pyrethroid that can be applied to cranberry, with Danitol being the first. Fanfare is registered for use in Wisconsin on several crops including bushberries, caneberries, grapes, pears, and strawberries, yet cranberry is NOT on the label. Fanfare received a supplemental label specifically for cranberry in 2021 and this will expire in December 2024 unless it is renewed by the registrant. Fanfare is marketed by Adama Essentials under the formulations EC or ES with 2 lbs of active ingredient per gallon as an Emulsifiable Concentrate (EC) or Suspension Concentrate (ES). Adama will likely work to get cranberry added to the label but in the meantime, every grower that purchased and plans to use Fanfare this season MUST have the supplemental label (in addition to the label) in hand as cranberry is not on the official label.

Mode of action and effect. The active ingredient in Fanfare is bifenthrin. Fanfare is in the class of the pyrethroids (IRAC group 3), which have a mode of action that targets the sodium channels on the axon of the neurons. Pyrethroids cause a prolonged depolarization of the neuron from a prolonged influx of sodium into the neurons, leading to repetitive nerve activity that can result in hyperexcitation, paralysis, and death. Fanfare is an insecticide with foliar activity that is fast acting by contact or ingestion of treated plant surfaces. Affected insects will rapidly stop feeding, become paralyzed, and eventually die.

Fanfare has broad spectrum activity on several insect species, found on the supplemental label for cranberry, including fruitworms, tipworm, fireworms, spanworms, flea beetle and white grub adults. In our trials in NJ, Fanfare was very effective at controlling leafhoppers. Leafhoppers are not specifically mentioned as target pests on the supplemental label; however, in NJ, you are allowed to use products on pests not present on the label, as long as the product is labeled for the crop you are applying it to.

Application restrictions. Fanfare may be applied by ground equipment, chemigation, and air, and specific recommendations are provided for the different application methods regarding direction for use, spray drift requirements, and buffer zones. Buffer zones from aquatic habitats are specifically stated in the label, with a minimum 10-foot wide vegetative strip of grass or other permanent vegetation between the field edge and aquatic habitats. For more information on mixing and spraying, and all other considerations, please see the product label.

Environmental impacts. Fanfare is extremely toxic to fish and aquatic invertebrates and cannot be applied directly to water. It must be used with care (see buffer zones restrictions) when applying in areas adjacent to bodies of water. Fanfare is highly toxic to bees exposed to direct treatment or residues on blooming plants. Do not apply Fanfare when bees are foraging and until flowering is complete. The label also emphasizes the risk to endangered species and prohibits the use of bifenthrin in areas that could result in exposure to endangered species.

Recommendations. Overall, Fanfare is recommended against leafhoppers before bloom to target leafhopper nymphs. The reason for this recommendation is that we already have great products to target other insect pests at our disposal that have much lesser impacts on the beneficial insects, including pollinators and natural enemies of these pests. The environmental concerns raised above and the acute toxicity of this compound play an important role in recommending limiting the use of Fanfare to a single pre-bloom application to minimize pesticide residues and environmental impacts. Finally, a 3-day water holding is highly recommended when using this product to allow the product to bind to soil particles and reduce movement of the product in the water system.

Please check with your handlers before using a new product as handlers may have restrictions on certain products for domestic and/or foreign markets. Handlers may extend PHIs beyond the number of days stated on the label to reduce residues, so please always check with your handlers. As of 2022, several handlers have imposed a 120-day PHI on this product. And as always, make sure to read the labels before using any pesticide.

Resources. You can find the labels for Fanfare at the following links:

Fanfare EC Label: http://www.cdms.net/ldat/ldC86005.pdf

Supplemental Label for Fanfare EC for cranberry use: http://www.cdms.net/ldat/ldC86002.pdf

Fanfare ES Label: http://www.cdms.net/ldat/ldB3C005.pdf

Supplemental Label for Fanfare ES for cranberry use: http://www.cdms.net/ldat/ldB3C000.pdf

This article was written by Ocean Spray, Lindsay Wells-Hansen (Sr. Agricultural Scientist) and Dave Jones (Agricultural Scientist), who were kind enough to share the information with all New Jersey growers. Independent growers should consult their handlers for PHI restrictions and any other limitations before making purchases or applications.

Beginning in 2022, the use of chlorpyrifos (e.g., Lorsban) is no longer allowed in any capacity for either EU or non-EU Qualified fruit. This includes existing stock – NO chlorpyrifos may be used going forward, even if a grower has already acquired the material in a previous season. While the loss of this broad-spectrum material is a challenge, we have several efficacious materials that can be used as a chlorpyrifos replacement for pre-bloom insect control. The list below includes some of these materials and highlights which insect pests can be targeted with each insecticide. We’ll focus on pre-bloom management of two pest groups: (1) Lepidoptera pests (Leps) which are caterpillar species including Sparganothis, fireworm species, spanworms, cutworms, etc. and (2) blunt-nosed leafhoppers (BNLH).

• Acephate (e.g., Orthene). This material will control both BNLH and Leps. There is historical concern among some growers that acephate used prior to bloom deters pollinator activity and reduces yield. This was investigated by the WI Ag Science team in 1990/1991 and again in 2020/2021 and no significant relationship between pre-bloom acephate and pollinator activity/yield was ever observed.
• Spinetoram (e.g., Delegate). Spinetoram is a strong material for managing Leps but is NOT effective for controlling BNLH. This material is a valuable rotational material because it is specific in its efficacy, thus preserving beneficial insects.
• Sulfoxaflor (e.g., Closer). This material is ONLY useful for the control of BNLH. It will NOT work against Leps, but it can be applied in conjunction with a lep-specific chemistry (like Delegate) if control of both pest groups is needed at the same time.
• Fenpropathrin (e.g., Danitol). Currently ONLY available for use on non-EU Qualified fruit. This pyrethroid insecticide is relatively new to the industry. The pyrethroid class is relatively broad-spectrum and should provide control of both BNLH and Leps.
• Indoxacarb (e.g., Avaunt). This material should work well on most Leps, but there is some evidence that it provides moderate to poor efficacy against Sparganothis. Its efficacy against BNLH is unknown, but it is not listed as a strong material for leafhoppers in other crops.
• Methoxyfenozide (e.g., Intrepid), Tebufenozide (e.g., Confirm), and Novaluron (e.g., Rimon). These three materials are insect growth regulators (IGR’s) that ONLY target Leps. None of these materials will provide control of BNLH. Intrepid and Confirm are both minimally toxic to bees and can be applied during bloom, but Rimon should NOT be applied during or immediately prior to the bloom window.
• Cyclaniliprole (e.g., Verdepryn). Currently ONLY available for use on non-EU Qualified fruit. Verdepryn is another relatively new material to the industry. It is a diamide, which is the same class of insecticide as Altacor and Exirel. The diamides generally provide strong control of Leps. The efficacy of Verdepryn against BNLH is not currently known.
• Bifenthrin (e.g., Fanfare/Capture). This pyrethroid insecticide is newly available to the cranberry industry in 2022. A 120-day PHI restriction has been placed on the material for EU-Qualified fruit this year. The PHI restriction for non-EU Qualified Fruit is 45 days. This material is also restricted to a single application per season. It will provide control of both BNLH and Leps.

Growers are reminded that the 2022 OSC Code Book should be consulted prior to the application of ANY of these materials. Application timing is particularly critical with the softer chemistries on this list; weekly scouting must be incorporated in order to deploy them effectively. Many of these materials are hard on bees – always consult the label for bee health hazards prior to application.