Fruit IPM for 8/18/21

Grapes:

Drosophilds and Sour Rot: As the sugars start to increase in early verities like Chardonnay, be aware of Spotted Wing Drosophila combined with native fruit fly species. These populations  increase at this time of year and help spread sour rot. Sour rot will only be present when you also have injured fruit. Fruit splits and various insects can help cause that initial injury. It is thought that the spotted wing drosophila (SWD), because of its saw-like ovipositor, can help cause this initial injury, helping to make the fruit more attractive to native drosophilid species.  After injury the fruit serves as a food source for ethanol-producing yeasts and acetic acid producing bacteria, the causal agents of sour rot. This in turn attracts more fruit flies to lay more eggs and spread the decay. Good canopy management for air circulation is useful to reduce sour rot incidence. However, this must be combined with insecticides and antimicrobials. A treatment regime that consists of weekly applications of an insecticide (Mustang Maxx (or other pyrethroid), Malathion, Delegate/Entrust,  + Oxidate 2.0 has been found to be helpful. Other sterilants can also be used. Since it is important to rotate insecticide classes when treating this often, growers should use no pyrethroid or other insecticide class more that 2 times in a row. These treatments should be started before the onset of visible sour rot and fruit fly presence.

Spotted Lanternfly (SLF): SLF adults are moving into vineyards statewide, and populations vary greatly depending on location. While there are no known treatment thresholds, we do know that the adults can be much more problematic than the nymphs, and it is likely that adult populations will only increase from now through the end of the season. Some researchers feel that the presence of 5 or more adults per vine will merit control. As the insects start to move into the vineyards, numbers can change quickly. Make sure to look at edge rows first, since this is primarily an edge pest.

Blueberries:

General: Updated from last week – All fruit has been harvested. Therefore we are only concerned with post-harvest pest issues. These include 1) Spray timing for 2^nd generation sharpnosed leafhopper, 2) Treating any fields that had or have Putnam scale populations – timing for crawler activity, and 3) Post harvest applications of fungicides for black shadow control.

Putnam Scale: There are 2 generations per year of Putnam scale, and the insect is most sensitive to control when in the crawler stage. Eggs that are under the scale covering of adult females start to hatch in early August and nymphs emerge and spread out to new cane growth and leaves. Peak nymph emergence and movement is usually around mid-August, and therefore when treatments should be applied if you had any fields with scale presence during June to early July, or the first generation. Last week our trap counts averaged 33.57 nymphs per trap with a high of 108, this week’s average was 70.28 with a high of 207 crawlers per trap. Therefore we are in the thick of crawler emergence and it is time to treat. Make sure to use a high volume spray, since you are trying to cover the entire cane and twig surface. Use as close to 100 gal./Acre as you can. These insects do not ‘fly into’ residual insecticide. Rather they must be thoroughly covered when making the application, and the insecticide must reach into all the bark crevices where nymphs might be settled. Diazinon and Esteem are the products of choice. One field treated with Diazinon (100 gal/A) last week showed good control

Sharpnosed Leafhopper (SNLH): Insecticides are timed for the second generation of adults, and rarely do Putnam scale and Sharpnosed leafhopper ‘cooperate’ so they can be treated at the same time. This is also true this year. So while growers need to treat for scale now, it is still too early for any second generation treatments targeting SNLH. We are averaging only .62 SNLH per trap in Atlantic County and .08 SNLH per trap in Burlington County.

Black Shadow:  On average we are finding black shadow presence on 39.72 % of canes per bush and a high of 100% of canes per bush. Those growers with significant black shadow on their bushes may wish to follow recommendations published earlier by Dr. Peter Oudemans. For more information please see earlier articles on black shadow:

https://njaes.rutgers.edu/blueberry-bulletin/pdfs/2020/bb-v36n23.pdf

https://njaes.rutgers.edu/blueberry-bulletin/pdfs/2021/bb-v37n01.pdf

Peach:

Oriental Fruit Moth: Oriental fruit moth is between generations and populations are low. On average, no treatments are needed for this pest at this time unless trap counts exceed 8 moths per trap.

Brown Rot: Brown rot pressure remains very high. See last week’s newsletter and the Tree Fruit Production Guide for suggested controls.

Apple:

Brown Marmorated Stink Bugs (BMSB): Populations are generally low in southern orchards, but slightly higher in northern counties. Some locations in Hunterdon County have 11 nymphs per trap, accompanied by low amounts of recent fruit injury. In these situations, pyrethroid insecticides applied every 7 days are required, and perhaps more often around the orchard borders, especially if heavy rains wash off previous applications.

Woolly Apple Aphid (WAA): In a few northern orchards WAA colonies need treatment. Levels at one location were more than 30 colonies per tree. This insect can be difficult to control. Diazinon and high rates of Closer (2.75-5.75 fl oz/A) are suggested for control. Use a high spray volume to penetrate and completely cover all woody surfaces.

Codling Moth (CM): In general trap counts are very low, indicating no treatments are needed for this insect. However, several locations have trap counts greater than 5 moths per trap. Growers where these high counts are present should continue treatments with CM effective materials.

Tree  Fruit Trap Counts – Southern Counties

 Tree  Fruit Trap Counts – Northern Counties