Fruit IPM for 5/18/21

Peach:

Oriental Fruit Moth: First generation timings are updated below. Growers that have utilized mating disruption for OFM can focus on PC; GPA; and catfacing insect pests as described below.

The timings for first generation OFM are over for all regions. Second generation timings will be in about two weeks in southern counties. Overall the adult population is low, but above the treatment threshold of 8 moths per trap on some farms in northern counties.

Plum Curculio (PC): PC activity usually peaks about mid-May and may linger into early June. This year adult PC activity has been light, due to the cooler weather. However, this will change quickly as we move into warmer weather patterns. This may actually extend PC activity slightly later in the season. Preferred materials that offer PC control now are Avaunt, and Imidan. If using high rates of a neonicotinoid (i.e. Actara, Belay, Assail), be aware that there is a synergistic effect when used in tank mixes with DMI materials (i.e. Rally) with regard to bee toxicity. Neonicotinoids should not be used if there are any flowering weeds in your orchard. Those flowering weeds will attract bees, which will be killed by the insecticide. The use of most of these products when bees are present is off label and therefore not legal. If pyrethroids are being used, then high rates are advisable, since low rates often do not control PC, especially in hot weather. Where PC is a problem, growers should rotate away from pyrethroid insecticides if possible. Actara and Belay will also control PC (and GPA), but not OFM. Fresh injury and activity was seen this week in both southern and northern counties.

Fresh PC egg laying scar on 5/15/21 in northern counties.

Green Peach Aphids (GPA): GPA colonies remain at very low levels in southern counties, and are well below treatment thresholds. If aphids are at treatment level, and your ground cover is clean of blooming weeds, a good choice that will cover catfacing insects, aphids, and plum curculio is Thiamethoxam (Actara and in VoliamFlexi). Actara will not control OFM. Examine trees for the presence of colonies by standing back and looking at the entire tree. Clusters of curled leaves will define a single colony. Count the number of colonies on ten trees and use a treatment threshold of 2 colonies/tree at petal fall to shuck split for peach, and 1 colony/tree for nectarine. If treating aphids alone then Movento @ 6 oz/A is a good non-neonicotinoid choice. Movento must be combined with a spreader/penetrant spray adjuvant. Used later during late May to early June this will also control scale. Movento will not control PC or catfacing insects. Lannate can also be used, but is not quite as effective and is a weak PC material. To date no aphids have been observed in southern county orchards.

Tarnished Plant Bugs and Other Catfacing Insects:  This is the other key insect complex at this time of year. Stink bugs have been found at low levels in beating tray samples. Tarnished plant bugs will become more of an issue as temperatures warm and mowing and other ground cover activities become more common. General spray timing at this time of year should still be targeted for Oriental Fruit Moth and/or Plum Curculio (PC). Most OFM materials, except Altacor and Exirel, will have some efficacy for plant bugs.

Scale Insects: White peach scale (WPS) crawlers are very close to emergence in southern counties. San Jose scale (SJS) crawlers usually begin emergence about a week or ten days later, usually late May/Early June. If you have scale infestations on your trees, it is important to note if crawlers are present, even if you treated with oil in the early spring. If crawlers are present then treatment options include Esteem, Movento, Centaur, Venerate, and Diazinon. Esteem, Centaur, Venerate and Movento should be applied at the beginning of crawler emergence. Venerate needs to be applied at the low rate of 1 qt/A. Diazinon is labeled for only one post bloom or foliar application on stone fruit (Rec = max. of 2 lb/acre of the 50W). The apple label allows up to 2 foliar applications per year as long as a prebloom application was not made. The peach label allows 1 foliar application per year. Foliar applications may cause russet on apples, but has worked in the field for scale crawlers as long as applications are made 1-2 weeks after the start of crawler emergence and again 2 weeks later. Belay and Assail are also effective against scale crawlers but may need more than one application during the emergence which typically lasts about 4 weeks for WPS and 6 weeks for SJS.

Lesser Peach Tree Borer and Peach Tree Borer: Lesser Borer adults began flying last week in southern counties. If you haven’t placed mating disruption dispensers yet there is still time to get them out before the greater peach tree borer flight which usually begins in June.

Bacterial Spot: Maintain tight covers with antibiotics until pit hardening. Typical antibiotics used include various copper and oxytetracycline formulations. Full covers with at least 100 gpa are recommended around wetting periods or severe weather. No bacterial spot cankers or leaf symptoms have been observed in southern county orchards as of yet.

Peach Scab: In addition to Rusty Spot and Bacterial Spot, peach scab requires protective applications starting at petal fall. Peach scab cankers begin to expand at bloom and by shuck split begin to shed spores during wetting periods. Topsin, Topsin/Captan combinations, Flint Extra, Inspire Super, and especially Quadris Top applied at petal fall are the best materials for blocks that had scab last year. Quadris Top, Flint Extra and Topsin should be used at the high rate to suppress overwintering lesions on the wood. Quadris Top contains azoxystrobin which is phytotoxic to many apple varieties. Phytotoxic residues can remain in the tank for long periods after an application is made, even if a tank cleaner is used. Do not use Quadris Top or Abound in the same sprayer used for apples. Bravo (chlorothalonil) is also a good protectant that may be applied no later than shuck split. Captan is also helpful in cover sprays after shuck split where scab was troublesome last year. Maintain effective scab materials in cover sprays through June.

Rusty Spot: Rusty spot infections are ongoing until pit hardening. If you are using Flint Extra, Inspire Super, or Quadris Top for scab, these materials will also control rusty spot. After petal fall, maintain coverage with effective materials such as Rally, Rhyme, or potassium bicarbonate products.

Apple:

Codling Moth (CM): Biofixes for Codling moth have been set. See the chart below. Timings for codling moth treatments by chemistry are listed below.

European Apple Sawfly (EAS): Sawfly larvae began hatching sometime in the past two weeks. Damage is now visible in apple plantings. This is one of the key pests to control now, especially if you have mixed variety plantings with wooded borders. See photo below.

European Apple Sawfly damage in soutthern counties on 5/15/21

Tufted Apple Budmoth (TABM): A biofix was set statewide on May 3. The first alternate middle applications for TABM will be on or about May 28 in all counties. This has been considered a minor pest in recent years. With the exception of Assail and other sucking insect materials, and granulosis virus formulations (e.g. Madex), most materials used for Codling Moth will control TABM.

Diseases: Apple Scab, Powdery Mildew, Cedar Apple Rust, are diseases of concern at this time. The NEWA scab models calculating about 100% ascospore maturity in southern counties and about 95% maturity in northern counties. No immediate infection periods are in the 5 day forecast, but a prolonged wetting period could yield a severe infection period with this many mature spores. Primary apple scab spores are released during any substantial wetting and infection period, and since most ascospores are mature, primary scab season is nearing the end in all counties. Watch the forecast so your orchard can be well covered in the event of a prolonged wetting period. Growers should continue to manage for primary scab through May since microclimates may affect spore maturity and because it has been dry the next significant wetting may still result in a primary scab infection.

Cedar apple rust infections can occur anytime between pink and 3^rd cover. Summer diseases such as rots and sooty botch are beginning to overlap with early season diseases. Most scab materials will control summer diseases. Growers who have had trouble with bitter rot may wish to include a phosphonate product (e.g. pro-phyt) with captan. Phosphonates contain potassium and my contribute to bitter pit so avoid the use of phosphonates on Honeycrisp until after cell division is complete, usually sometime after the thinning window has closed.

Grapes:

Diseases: Grape diseases active at this growth stage are phomopsis, powdery mildew and black rot. Disease infection periods can be monitored using the NEWA models. Choose the weather station closest to your vineyard.

Insects: Leafhoppers have been seen in a few spots. This complex is generally not of concern. Potato leafhoppers, which arrive sometime in June, can cause some minor damage. Spotted Lantern Fly nymphs are now hatching statewide. These nymphs do little damage and generally don’t need special treatments when present. Even so, vineyards should be monitored for SLF presence and if they are found use an insecticide effective for SLF when treating for Grape Berry Moth in late June.

Scouting Calendar Tree Fruit Southern Counties

The following table is intended as an aid for orchard scouting. I t should not be used to time pesticide applications. Median dates for pest events and crop phenology are displayed. These dates are compiled from observations made since 1995 in Gloucester County. Events in northern New Jersey should occur 7-10 days later.

Tree  Fruit Trap Counts – Southern Counties

Tree  Fruit Trap Counts – Northern Counties

Blueberries:

Leps and Other ‘Worms’: This past week’s scouting, Lep larvae averaged .04 per bush with a high of 0.5 larvae per bush. Most of these were  green fruitworms and spanworm. Some Gypsy Moth were still being found in Atlantic and Burlington Counties. Gypsy moth larvae averaged 0.05 larvae per bush with a high of 1.7. The treatment threshold is 1 per bush of any combined lep larvae. With gypsy moth presence the treatment threshold should be slightly less. Overall, there were about 3 times the level of gypsy moth larvae on lower shoots than on higher shoots. Therefore make sure your spray coverage reaches those lower shoots when treating for gypsy moth.

Plum Curculio: This past week’s scouting for plum curculio showed an average of 0.68 with a high of 7.8 injured berries per bush. As the weather warms up, we may see an increase of PC activity in unsprayed fields. In a ‘normal’ year PC is the main pest to control in the first post pollination spray. Imidan and Avaunt are 2 of the main choices.

Aphids:  Aphids normally start to appear a little later in the season. However, we started to see aphids starting to build up this past week. Colonies are small, with the average shoot infestation level of 3.6% of shoots infested, with a high of 40% infested. Our provisional treatment threshold is set at 10% of shoots infested with aphid colonies. Given the fact that we have recently seen an increased levels of scorch virus, it is very important to keep aphid levels down. Most aphid colonies are found on the lower shoots. The materials of choice include Actara, Assail, Admire, and Sivanto. If you are having trouble reaching the bottom shoots, then Movento may be an option (should be used with a spreader), since it moves both up and down in the bush.

Cranberry Fruitworm Traps:   CBFW average per trap was 0.012 with a high of 4.