Archives for May 2024

Peach:

Bacterial Spot: Copper formulations should be used starting at petal fall to suppress bacterial spot. Generally we recommend starting at 0.5 ozs metallic copper and gradually lowering the rate as the season progresses. The rate applied will depend on the formulation. Dr. Lalancette published a chart listing common copper formulations and rates for peach and nectarine applications. Avoid combining copper with captan especially if it has been overcast for several days. Also avoid acidic spray solutions when applying copper. Dr. Lalancette has published a handy guide for copper applications in early covers. Antibiotics containing oxytetracycline may also be used and may offer slightly more residual activity during long wetting periods. We have not seen any bacterial spot symptoms as of this writing except for one location in a northern county. We are nearing pit hardening which usually occurs mid-June. Once fruit gets to this stage it develops some resitanceto bacterial spot. Infections may still occur but will be less severe.

Oriental Fruit Moth: A biofix point for OFM was set on 4/10 in both northern and southern counties.  All Treatments for the first generation have past.

Plum Curculio; Tarnished Plant Bugs; and Other Catfacing Insects: Plum Curculio start to move into orchards at about 88-100 degree days base 50 after January 1. Applications for PC should be initiated once all petals are off, with a second application made with ovicidal materials at 379-402 DD. Currently we have accumulated about 661 DD base 50 in southern counties, and 552 DD base 50 in northern counties. Growers can monitor degree day development at their site by finding the nearest weather station and using the degree day development tool at NEWA. PC and Catfacing insects are active now and can cause injury.

Scale Insects: White peach scale crawlers began emergence around mid-May in southern counties and San jose scale crawlers typically begin emergence about late May or Early June and continue emergence for up to 6 weeks. Control options during crawler emergence include Neonicitiniods (suppression only), and the IGR’s Esteem and Centaur. See the NJ Commercial Tree Fruit Production Guide and the product labels for more information.

Apples and Pears:

Diseases: Now that primary scab is nearing the end, or has ended, the focus turns toward summer diseases such as fruit rots (esp. Bitter rot), and sooty blotch and fly speck. Bitter rot control has been difficult at best in recent years even where management programs have been rigorous. Research has suggested Products such as Merivon, Luna Sensation, Inspire Super, and Aprovia may be effective, and longtime reliable broad spectrum fungicides such as omega, captan and ziram should provide control. Experience has suggested that the addition of phosphorous acid products such as Prophyt or Rampart to captan sprays may improve control. Observations are that these products improve control of other summer diseases such as sooty blotch and flyspeck, and may help suppress scab infections where present.

Fire Blight: Fire Blight symptoms began appearing in southern county apple and pear orchards the week of 5/20, and in northern counties the week of 5/13. Typically it is recommended to cut out infected limbs however this is a practical decision that must be made. This blog post from Michigan State may be helpful to decide whether it is worth cutting out infected tissue. Once the terminal buds set, typically in July, infected wood should be removed to prevent colonization by the bitter rot pathogen.

Codling Moth: A Codling Moth Biofix was set in southern counties on 4/22 and on May 1 in northern counties. See the NJ Commercial Tree Fruit Production Guide for recommended materials and rates. Where Mating Disruption has been employed, supplemental Madex applications should be made at the timings listed below.

Tufted Apple Budmoth (TABM): A biofix for TABM was set in southern county orchards on 4/30. The first alternate middle applications for TABM will be on or about 5/24 in southern counties. This has been considered a minor pest in recent years. Many materials used for Codling Moth will also control TABM.

Scale Insects: Dormant oil applications are standard recommendations for scale control but in some years when conditions are not optimal for oil application scale control may be less than desired. Where oil was not applied or in orchards where scale is a recurring problem, an application of Centaur at petal fall or Movento between petal fall and first cover should “clean up” problem blocks. Centaur is recommended at 34.5 ozs./ac and Movento should be applied at 6-9 ozs./ac. A penetrant must be included to Movento as per the product label. Movento will also control apple aphids, including Wooly Aphid, when used at this timing. In pears Movento may also control aphids and 2nd generation pear psylla (if eggs are present) when applied at first cover.

Ambrosia Beetle : Infested trees are showing signs of stress. If you have had a history of this pest in your orchard, you should begin scouting for damage and remove any trees that have been attacked. It may be beneficial to leave attacked trees in the orchard for a few weeks before removal so they can act as trap trees to reduce populations. Beetles generally do not leave the host tree once they’ve attacked it. They will attract other beetles to the stressed tree and adjacent trees so they tend to stay in one area rather than spread throughout the orchard. Recently infested trees were taken to Rutgers Plant Diagnostic Clinic and the species attacking the trees was identified as Granulate Ambrosia Beetle, one of two ambrosia beetle species known to attack orchard fruit trees in NJ, the other being Black Stem Borer.

Wooly Apple Aphid (WAA); Green Apple (Spirea) Aphids (GAA): GAA colonies are beginning to appear in some apple blocks. GAA is generally a pest that can be tolerated since they do little direct damage. Treatment thresholds for GAA are if 50% of the shoots are infested with no beneficial insects present. WAA aerial colonies are also beginning to form in southern counties. This is about a month earlier than usually observed. In most years these are controlled by beneficials however in some years like 2022, serious outbreaks can occur. The best control for WAA is Movento applied before or when the first colonies appear. Diazinon is also effective at knocking down infestations. Movento will also control GAA and should control san jose scale when applied in mid-May, and suppress scale when applied in late May or early June.  Do not combine Diazinon with Captan.

Potato Leafhoppers (PLH): PLH adults began appearing in apples this past week. PLH should not be tolerated in non-bearing orchards because they can stunt the growth of new shoots. Likewise they should not be tolerated in orchards were fire blight is present because they have been demonstrated to spread the disease. PLH appear as light green smallish leafhoppers and are often found on the new leaves in the growing tips. Neonicitiods are generally recommended for control however there are other braod spectrum materials that are effective. Refer to the NJ Commercial Tree Fruit Production Guide for more information.

Pear:  Second generation pear psylla began hatching about 5/15. Options for control include spynosyn products such as Delegate and Entrust, and the neocitinoids (IRAC group 4A). The addition of 0.25-1 gal of summer oil may improve control. Other options include Movento, the IGR’s Esteem and Centaur, and products containing abamectin. Be sure to read and follow the label instructions regarding the addition of penetrants for abamectin products. Pear Psylla are still actively laying eggs and nymphs continue to hatch.

Grape: Early blooming native grapes were at trace bloom on 5/24, therefore we have set the the Grape Berry Moth biofix at 5/24 for southern counties. Since V. riparia typically blooms with early natives we used Concord and Ives to set the biofix. The model works best when growers record their own bloom dates and use the Grape Berry Moth model at NEWA. Applications for GBM using Intrepid or Diamides should be made at 810 DD base 47. Other effective materials can be applied a few days later. Currently we are at 420 DD in southern counties. Applications have been historically made around the end of June in southern counties.

Phenology Table: Based on annual observations made in Gloucester County.

Tree Fruit Trap Captures – Southern Counties

Tree Fruit Trap Captures – Northern Counties