Fruit IPM for 5/20/20

Peach:

Plum Curculio (PC): As the weather gets warmers, we should see a lot more of PC adult activity. They have been active, at various levels for the past 5 weeks, and can be problematic especially around petal fall and shortly thereafter. Therefore make sure to include a PC effective insecticide in your petal fall spray (northern counties) if not already done so. Effective materials include: Imidan, Avaunt, Apta (has a bee caution label), and several neonicotinoids: Actara, Belay.

Oriental Fruit Moth: The second application for the first generation was due in southern counties early this week. The second application in northern counties is due very early next week. Make sure to use insecticides that are effective for OFM and PC and TPB, especially if you have weedy ground cover. Imidan and Avaunt are 2 single ai materials that are effective. As long as the weather remains below 80⁰, pyrethroids will also work. If you maintain a weed free ground cover, then the likelihood of killing bees is dramatically reduced.  First generation timings are updated below:

Tarnished Plant Bugs (TPB) and Other Catfacing Insects:  This is the other key insect complex at this time of year. Tarnished plant bugs will become more of an issue as temperatures warm and mowing and other ground cover activities become more common. Maintaining a weed free ground cover almost negates the need for TPB treatments.

Green Peach Aphid (GPA): Aphids have hatched and are showing spotty population increases, especially in some northern county orchards where over 2 colonies per tree have been seen. In general, a mature peach tree can tolerate 5-6 colonies/tree before treatments are needed. This is different for nectarines where GPA can feed directly on the fruit. Tolerate only 1 colony per tree on nectarines. Insecticides effective for GPA control include Movento, Closer, Beleaf, and any neonicotinoid or premixes that include neonicotinoids. Most neonicotinoids include a bee warning on the label. If your groundcover is not weed free, then bees will be actively foraging in the orchard, and the insecticide cannot be applied.

Scale Insects: San Jose scale (SJS) crawlers have not been observed as of this writing, but usually begin emergence about 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 is 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.

Bacterial Spot: Bacterial spot leaf symptoms are present in southern counties. Maintain coverage with the standard copper/oxytetracycline suppression program. Leaf infections appear water soaked, stay within the leaf veins, and gradually darken. (Last week’s photos are reprinted here – Figure 1.) Eventually the chlorotic tissue abscises from the leaf leaving a “shot-hole”. Copper injury appears similar. The main differences are copper injury will often appear at the leaf bottom where the spray collects as it runs off, and the shot-hole will cross over leaf veins. Copper injury often has a red appearance at the shot-hole margins.

Figure 1. Peach leaf with a mix of old and new bacterial spot lesions.

Figure 2. Copper injury to peach leaf.

Peach Scab: Maintain good coverage with captan or other effective fungicides until July where scab was an issue last year.

Rusty Spot: Rusty spot infections are ongoing until pit hardening. Maintain coverage with effective materials such as Rally, Rhyme, or potassium bicarbonate products. Other choices include Flint Extra, Inspire Super, Luna Sensation and Quadris Top, although usually at a higher cost.

Brown Rot: Maintain coverage with effective materials until pit hardening. Do not rely on sulfur alone unless a dry weather pattern develops. The Captan program, developed by Dr. Norm Lalancette would be a good program to follow, particularly as we get a little further into the growing season.

Apple:

Codling Moth (CM): Insecticide timings for codling moth are fast approaching. If you are using Rimon, the timing is now in southern orchards and slightly later in northern orchards. The use of any diamide should be around this weekend to early next week, depending on your location. If you are using Imidan, Delegate, Avaunt, Lannate, or any of the pyrethroids, then wait until the very end of the month. Avaunt’s strength is for PC and general Lep control. If you had high CM pressure last year, then try to use an alternative product.

Spotted Tentiform Leafminer (STLM): Adults are flying, but are not considered a pest target at this time.

Plum Curculio (PC): This is THE insect to control at petal fall. Avaunt, Imidan, Actara, Apta, and VoliamFlexi are the top options for control. Of these, Avaunt, Imidan and VoliamFlexi also do a good job controlling EAS (see below).

European Apple Sawfly (EAS): This insect one of the key petal fall insects to control, especially in orchard blocks with mixed varieties. Adult females lay eggs just under the skin of freshly set fruit, and the young larvae mine just under the skin.

Tufted Apple Budmoth (TABM): A biofix was set statewide on May 6. The timing for insecticide applications uses a 45⁰ base and needs 475 DD after biofix for the first application timing. As of 5/20 we have only had 235 DD accumulate in the Bridgeton area. So the treatment timings, if needed, will not be until early June in southern counties and by about mid-June in northern counties. With the freeze damage and sparse fruit set, this insect is not likely to be a problem worth treating.

Fire Blight: With exceptions of any late bloom still hanging on in northern counties, the high risk periods for fire blight are mostly over. This DOES NOT mean you should let your guard down if you have late bloom in your orchard or strikes that are present. Weather conditions are still predicted to be favorable for infection in far northern counties. Please see last newsletters for antibiotic and copper use suggestions, and the May 4 Scaffolds article by Anna Wallis and Kerik Cox at Cornell.

Scouting Calendar Tree Fruit Southern Counties

The following table is intended as an aid for orchard scouting. It 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

Blueberry

Plum Curculio (PC): PC activity has increased due to the (slightly) warmer weather over the past weekend. With temperatures increasing and bees coming out, the PC application should be your primary concern. Effective materials include Imidan, Avaunt, and Apta; which all also control cranberry fruitworm. Increased levels of PC injury to fruit have been seen. These will appear as the telltale crescent shaped egg scars as seen below.

Figure 3. Fresh plum curculio egg scar on young fruit (Photo – Carrie Denson).

Cranberry Fruitworm (CBFW): Traps were set out about 5 weeks ago, with the first adult captured on 5/8. This indicates that adults are starting to fly, mate and lay eggs. The key application for this insect has usually been during the first week of June, soon after the bees come out.

Leps and Other ‘Worm’ Larvae:  While a few green fruitworm larvae and small gypsy moth larvae are still being seen, populations are very low and don’t qualify as key pests to control when the bees come out.

Spotted Wing Drosophila (SWD):  We observed our first catch of SWD on Monday the 18^th in the Hammonton area. This is earlier than most years, but entirely expected, coming after the mild winter. These insects will be a key pest later as the fruit begins to color. For now they will seek out wild hosts and alternate crops such as strawberries on which to reproduce, resulting in higher populations when blueberries start to ripen and become susceptible. Successful SWD programs will use a 7 day schedule of rotating insecticide classes.

Figure 4. Adult male SWD (center) from trap capture. (Photo – Carrie Denson).

Botrytis, Phomopsis and Mummy Berry Strikes:  Disease has still been very minimal in the fields.  Most disease incidence levels are only showing up on 0.5% of bushes.

By the Numbers, Including Trap Counts: