Rutgers Cooperative Extension
Seasonal updates on diseases, insects, weeds impacting tree fruit and small fruit (blueberry, cranberry, and wine grape). Fruit Pest Alerts are also available via this category feed.
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Tufted Apple Budmoth (TABM): The first tufted apple budmoth adults were caught on 5/1 in southern counties. The first insecticides that target this pest will be due in a few weeks in southern counties. This has been only a minor pest during the last 6-8 years. [Read more…]
The following insect pests bear special mention for early-season scouting in cranberry bogs:
Blackheaded fireworm larva
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.
Spotted fireworm – overwinters as a 2nd instar larva. They complete two generations a year. 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, first generation adult moths emerge the first week of June, followed by a second-generation of adult emergence in early August. Eggs are laid in masses on weedy hosts. Larvae from second-generation adults emerge in mid-August, and may feed on fruit. Populations of spotted fireworm are regulated by their natural enemies, in particular Trichogramma wasps that parasitize the eggs.
Spotted fireworm larva
Sparganothis fruitworm – This insect is a serious pest in most cranberry-growing states. Sparganothis fruitworm completes two generations a year and overwinters as an early-instar larva. 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. Second-generation eggs are laid on cranberry leaves, and larvae will feed on fruit.
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 development. Because the first instars feed during the day (and also at night), scouting can be done during the daytime using sweep nets to estimate larval abundance. Larvae turn nocturnal during the later instars. At this time, 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 that lasts until the end of August and a pupal stage that lasts until October. Adults emerge from end of August to end of October.
Sparganothis fruitworm larva
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 the size of bogs). The action threshold for false armyworm, blossomworm, other cutworms, and gypsy moth (we use a combined threshold from adding all these caterpillars per sweep) 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 to 2 per sweep set. We recommend the use of the reduced-risk materials Intrepid, Altacor, or Delegate if populations exceed action thresholds. These are reduced-risk, softer insecticides that are very effective against lepidopteran pests. More information on these (and other) lepidopteran pests will be provided as the season progresses.
Cranberry blossomworm larva
Leafhoppers –There is concern among New Jersey cranberry growers of a potential increase in leafhopper populations because of recent changes in pest management strategies (e.g., adoption of new reduced-risk products and decreased applications of broad-spectrum insecticides). Blunt-nosed leafhopper is of particular concern because they can transmit cranberry false blossom disease. This leafhopper has one generation a year. Adults are found in highest numbers during July, although nymphs or adults may be found from the end of May until October. Eggs are laid in August-September. The eggs overwinter and hatch in May or June. The nymphs go through 5 instars to complete development.
Blunt-nosed leafhopper nymph
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 threshold based on sweep net counts, so decisions should be made based by comparing current numbers with prior infestation history and/or incidence of false blossom disease on those beds.
In cases of high numbers of blunt-nosed leafhopper nymphs, we recommend application of a broad-spectrum insecticide, such as Diazinon (no aerial applications allowed) or Lorsban (only pre-bloom applications allowed for Ocean Spray growers). 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.
With favorable weather conditions for germination and growth during the last few days, some of the summer weeds have started to emerge, including one of the most troublesome weeds in our blueberry plantations! Field bindweed (Convolvulus arvensis) is an aggressive rhizomatous perennial vine that belongs to the morningglory family. It spreads by seeds and by a deep, extensive root system. Reports indicate that seeds can persist in soil for up to 60 years, and that roots can grow up to 30 feet deep.
Field bindweed identification
Field bindweed trails prostrate along the ground until it comes in contact with other plants or structures. Stems will then rotate in a circular patter until it makes contact with a solid structure (overhead irrigation pipes, trees, blueberry bushes, other weed species, etc.), then it will wrap around the structure as it grows.
Seedlings (picture 1) emerged in spring. Cotyledons are square to kidney-shaped. Young leaves are alternate, bell-shaped with nearly parallel leaf margins and generally rounded tips. Leaf bases are lobed. No cotyledons are present when young plants emerge directly from the rhiz
ome. When juvenile stems are broken, they exude a milky sap. On mature plants, leaves are arranged opposite along the stem and are arrow shaped. Lobes at the base of the leaf point away from the petiole. Stems are smooth to slightly hairy.
Flowers (picture 2) are present from June to September and are trumpet shaped, pink to white in color. Field bindweed has two leaf bracts that grow from ½ to 1 inch below the flower, and is a key identification characteristic. Flowering is indeterminate, so flowers will continue to develop along growing stems until first frost
Field bindweed control
Mowing will not help to control field bindweed because the plant is growing prostrate on the ground (Picture 3). Cultivation may help to reduce bindweed growth and control it over the time but has to be repeated at frequent intervals. Once cultivated, it will usually take 2 weeks to the plant to regenerate fully functional above-ground vegetation, meaning that cultivation has to be repeated every 7 to 10 days. Consistency in cultivating bindweed-infested soils will promote the progressive depletion of carbohydrates stored in the root system by not allowing the plant to move back carboh
ydrates produced in the leaves to the roots. It is critical that NO timing be missed or be late! One single missed tillage can negate all the effort expended up to that point. Expect to continue the effort for 4 to 6 months! Success may require more time if the effort was not started when carbohydrate reserves in the weed were low at the start of the process.
Herbicides can be used to control field bindweed in nursery or mature plantations as long as NO herbicide is allowed to contact crop green bark, wounded trunk, leaves, or suckers. Applications of glyphosate containing herbicides (like Roundup) are effective as long as the herbicide is applied on plants that are actively growing and have flowers in late spring/early summer and late summer/early fall. Spring or fall applications may be more effective than applications made during mid-summer. Spot‑apply the higher percentage solution on the label of the product you use and thoroughly wet the foliage up to the drip point.
Repeated applications will be necessary, as the root system on this plant can be so immense that insufficient herbicide is absorbed with a single application. Use repeated applications, but allow the plant to grow and produce flowers before each subsequent application. More translocated herbicide will be moved to the root system when the plant is flowering than when vegetatively growing.
Fruit IPM for 5/1/17
Peach
Oriental Fruit Moth: First generation timings are updated below.
| OFM 1st Generation Timing | |||
| Insecticide Type | |||
| County/Region | Degree Days by 5/1 base 45 | Conventional
170-200, 350-375 |
Diamide
100-150, 300-350 |
| Gloucester – Southern | 390 | 1st – past
2nd – past |
1st – past
2nd – past |
| Hunterdon – Northern | 241 | 1st – past
2nd –5/9-5/10 |
1st – past
2nd – 5/6-5/7 |
Dear Fruit Growers,
The 2017 New Jersey Commercial Tree Fruit Production Guide is available electronically for free. Anyone may print paper copies if they choose to. If you already have a copy of 2016 NJ Commercial Tree Fruit Production Guide, you only need to print 10 page addendum (first 10 pages), available at: https://njaes.rutgers.edu/pubs/publication.asp?pid=e002.
Print copies of 2017 NJ Tree Fruit Production Guide available for $25 per copy.
For North Jersey, please contact: Diana Boesch: email – boesch@njaes.rutgers.edu or Phone – 908 -788-1339
For South Jersey, please contact: Joan Medany: email – jmedany@co.gloucester.nj.us or Phone – 856-307-6450 ex. 1
In spring, one 
of the first weeds that will break through the residual herbicide coverage provided by preemergence applications is horseweed, aka marestail. Horseweed has two primary periods of emergence, from late March through June and from late summer through late fall. Some of the most problematic horseweed emerges in the fall and over winters as small rosettes. If growers don’t control it with fall-applied residual herbicides, the weed has an excellent head start on the spring growing season, especially after a mild winter. Horseweed plants remain in the rosette stage through mid-April, followed by stem elongation (bolting) and rapid growth to an height of 3 to 6 feet. Plants that emerge the previous fall will bolt earlier than spring-emerging plants. Horseweed is most easily controlled when in the seedling, or rosette stage, and spring postemergence herbicides should be applied before stem elongation.
Treating them early is the key to success. Control of horseweed when its 2 to 4 inches is more likely than when it’s over 10 inches tall. Remember, most of the horseweed in New Jersey is resistant to glyphosate and there is a good probability that our populations are also resistant to ALS herbicides such as halosulfuron (active ingredient in Sandea) or rimsulfuron (active ingredient in Matrix). So, the most consistent options to control emerged horseweed include paraquat, clopyralid or glufosinate applied to small plants.
Paraquat – Use 2.4 to 4.0 pints/A of Gramoxone SL 2.0. Gramoxone is a contact killer that has no translocation or residual activity. So, best results will be achieved when seedlings are less than 1 inch in diameter. Two applications, two weeks apart are more effective than a single application. Regrowth may occur from the root systems of established weeds. Always use a nonionic surfactant (0.25% v/v) to improve the weed leaf surface in contact with the herbicide and enhance weed control. Do not allow spray or drift to contact green bark, leaves, or fruit as crop damage may result as shown on the picture. As Gramoxone targets the plant photosystem apparatus, applications made at sunset will increase weed control efficiency by allowing more herbicide to penetrate before being activated by sunlight in the morning.
DANGER: Do not breathe spray mist. Read safety precautions on the label.
Clopyralid – Use Stinger at 3 to 4 fl oz/A of. Stinger has a 24(c) Special Local Need label for weed control in blueberry since 2013. Stinger acts as both a postemergence foliar absorbed herbicide and a residual herbicide. The initial twisting and curling observed after application to susceptible species is due to the foliar absorption. Do not apply Stinger from one week prior to bloom until one week after bloom. Stinger can eventually be tank-mixed with Gramoxone to increase the spectrum of weeds controlled and defoliate existing foliage of perennial asters, goldenrod species and mugwort. Donot allow spray or drift to contact green bark, leaves, or fruit as crop damage may result as shown on the picture. Time all applications to maintain a 30-day PHI (PreHarvest Interval). Do NOT apply Stinger in a hand-held sprayer used to “spray until wet”. Stinger is a residual herbicide that must be applied on a rate per acre basis with a precisely calibrated sprayer. Read safety precautions on the label.
Glufosinate – Use Rely 280 at 48 to 56 fl oz/A. Rely is a foliar active, nonselective herbicide that controls a broad spectrum of emerged annual and perennial weeds. Best results are obtained when it is applied to actively growing weeds. Glufosinate does not provide residual weed control but can be tank mixed with residual herbicides for broad spectrum control. Contact of Rely with parts other than mature callused brown bark will result in extremely severe damages to the blueberry bush. Do not apply within 14 days of harvest. Warm temperature, high humidity, and bright sunlight will improve the performance of Rely. Read safety precautions on the label.
