Fruit IPM for 6/3/2020

Peach:

Plum Curculio (PC): PC oviposition is coming to an end in most counties. The Cornell model recommends that insecticides are only needed until 308 DD base 50 after apple petal fall. This was June 1 in southern counties and should be about June 5 in Hunterdon County and slightly later north of Pittstown. Therefore applications made this week in southern counties should control this generation of PC. In the southern part of the state we also have the southern strain PC, which has 2 generations per year. Therefore this may be a returning issue in mid-summer.

Oriental Fruit Moth: Most trap counts are very low, since we are between generations 1 and 2. There are some locations in northern counties with trap captures still at over 8 moths per trap. These growers should continue insecticides that are effective for OFM, even though the model timing is past (see below).

Bacterial Spot: Bacterial spot is present on the leaves in a number of orchards in both southern and northern counties.  Maintain copper sprays. If the crop load is very light, and you can still afford the copper, then treatments are still suggested.

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. Rusty Spot lesions are now appearing on susceptible fruit varieties in southern counties.

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.

Cherries and Spotted Wing Drosophila (SWD): Cherries are have been starting to color. This is a signal that they all need to be protected from SWD infestation. Any fruit that looks like the ones below needs and effective SWD insecticide program at regular 6-7 day intervals.

Figure 1. Cherries in Gloucester County at different ripening stages, and susceptible to SWD infestation.

Apple:

Codling Moth (CM): CM trap counts are very low, which is normal for having just finished treatments for the first generation.

Oriental Fruit Moth in Apple: There is a night and day difference between the populations in most orchards compared to some isolated spots in northern counties where trap captures are over 150 males per trap. If you have over 8 males per trap, then treatments are still suggested.

Plum Curculio (PC): PC is still active in some far northern counties with up to 9% fresh injury seen over the past week. These next few days are the last chance you have for control in those areas.

Tufted Apple Budmoth (TABM): A biofix was set statewide on May 6. The first alternate middle applications for TABM will be on or about June 3 in southern counties. This has been considered a minor pest in recent years. With the exception of Assail and Madex, most materials used for Codling Moth will control TABM.

Green Apple Aphids and Spirea Aphids: This green aphid complex is starting to show up in orchards, but not at treatable levels. In order to justify an aphid insecticide, you need at least 50% of the tree terminals infested with healthy dense colonies. This insect serves as a food source for many predatory insects, and is also a parasitoid host. Delays in treatments often result in higher beneficial insect levels, which can also help control other pests.

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): As of this writing, most growers have applied at least one application targeting plum curculio. In some cases the applications were followed by significant rains. In other cases low rates of pyrethroids were used, which do not give the best control. These are the likely reasons why in some areas we are still seeing some residual PC activity. This insect has been active for a very long time this season. The first berries to become infested are now blue and soft, and are starting to drop from the bush. Other injuries are only a few days old, and may not drop before harvest. When adults and fresh egg scars are no longer seen, then you can safely move on to other concerns. Some of the newest injury is being seen on Burlington County fields. There is little change in most Hammonton fields. The image below illustrates the length of time this insect has been active, with an old injury on a blue fruit ready to drop accompanied by a green fruit with a recent egg scar on the left.

Figure 2. Old PC injury on right and new egg scar on left (6/2/20).

Aphids: If plum curculio has been well controlled, the next week to 10 days will be good timing for aphid control. Aphids counts have increased to an average of 3.6% new growth infested with colonies, with a high of 22% on the lower shoots. Because the reproductive capacity can be so fast, we define a terminal as infested if there are one or more aphids on the terminal. At the present time most positive terminals have only single aphids.

Spotted Wing Drosophila (SWD): Trap captures remain very low, but the percentage of traps with captures has gone up over the last week. This indicates that while the populations are low, they are becoming more widespread. SWD insecticides will be needed as varieties become susceptible and start to color. With the frost injury we had, some of the first picking of Duke was nipped off, so instead of Bluecrop being right behind, some fields of Duke and Bluecrop may be picking at the same time. Some Bluecrop is starting to show a blush. Any fields starting to color should have something effective for SWD. In many cases this will be Assail, since it is effective for aphids and OK on low populations of SWD.

Lep larvae and Cranberry Fruitworm (CBFW) Injury: Total worm injury to fruit has decreased, and no CBFW injury has been seen to date.