Archives for August 2023

Peach:

Borers:  Where mating disruption dispensers are used there should be no need for butt sprays. If mating disruption was not used, the only other options are pyrethroids with a label for the use. The New Jersey Commercial Tree Fruit Production Guide recommends either Asana or Pounce. Pyrethroids lack a long residual so our recommendation would be a late August/early September butt spray followed by an additional application in mid to late September. Since this would be a labor intensive practice it would be most efficient to give priority younger and most productive orchards. Remember to follow the label as to the maximum allowable amount per season of either material.

Apples and Pears

Brown Marmorated Stink Bugs: Brown Marmorated Stink bugs are nearly absent in orchards statewide, likewise native stinkbug populations have been very low. If stinkbugs are a concern for your orchard, see the NJ Tree Fruit Production guide for effective materials. If treatment is needed for orchards near harvest. Venerate has a +++ rating for stink bugs and a 0 day PHI. In tests conducted by Dr. Neilsen’s lab, Venerate always performed better when applied at half the highest labeled rate.

Codling Moth (CM): Second generation treatments according to the degree day model are now over. Additional treatments should be made if trap captures are over 5 moths/trap. Most orchards have very low CM pressure, however a few orchards have had continuing trap captures above threshold.

Summer Diseases: Disease control is over for early season apple varieties. Mid to late season varieties will need further applications on a two week schedule until mid september for sooty blotch and fly speck.

Lesser Appleworm: In 2022 some orchards in southern counties have had internal worm damage that we think was Lesser Apple Worm. This sporadic pest sometimes shows up in late summer and fall. The damage is similar to codling moth. Larvae complete their life cycle quickly and often by the time damage is seen the larvae is already gone. Typically LAW will feed in the fruit calyx and not go into the flesh, however they may also feed on fruit flesh excavating a small hole under the skin and occasionally tunneling into the fruit. Control options are the same as for codling moth. LAW can be monitored using traps baited with OFM pheromone.

Grape

Bunch Rots: Disease management continues to focus on downy and powdery mildew and also turns to bunch rot management. Refer to the NJ Commercial Grape Production Guide as well as the linked presentation from Dr. Nita in Virginia.

Grape Berry Moth: The timing for the third generation is past. In some hot summers a fourth generation may occur, however no further treatments should be needed, especially where insecticides are being applied for SLF and SWD.

Drosophila’s and Sour Rot: SWD adults are being caught in and around commercial vineyards. 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 pres ent 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, Verdepryn).  Add Oxidate 2.0 if fruit cracking from rain or other causes is observed. 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 Lantern Fly: Spotted lantern fly adults are not yet appearing in vineyards, however they should be soon. When the first adults are observed, border treatments with effective materials should be adequate since most adults will be found on vineyard edges and populations will be low. As we move into September adult migration will increase and at that point growers should apply materials with long residual efficacy (refer to the table from Penn State below.) More information on biology and control can be found from Penn State.