Fruit IPM Report May 26, 2025

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 seen minimal bacterial spot symptoms. We are nearing pit hardening which usually occurs mid-June. Once fruit gets to this stage it develops some resistance to bacterial spot. Infections may still occur but will be less severe.

Oriental Fruit Moth: A biofix point for OFM was set on 4/2 for southern counties and 4/17 in northern counties. All Treatments for the first generation have past.

Green Peach Aphid: We are still observing aphid colonies above threshold at some farm sites. If more than 1 colony of aphids are found in nectarines, or 2-3 colonies are found in peaches, an insecticide for aphids. See the NJ Commercial Tree Fruit Production Guide for recommended materials and rates.

Tarnished Plant Bugs; and Other Catfacing Insects: Catfacing insects are active, and activity will increase with dry weather and summer temperatures. Very little recent fruit feeding has been observed.

Figure 1. San Jose scale crawlers on peach. Photo by Dave Schmitt.

Scale Insects: White peach scale and San Jose scale crawlers (Figure 1) began emergence this week and will continue emergence for up to 6 weeks. Control options during crawler emergence include neonicotinoids (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, Omega, and Aprovia may be effective, and longtime reliable broad spectrum fungicides such as 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. Scab symptoms are appearing in some orchards statewide.

Fire Blight: Fire Blight symptoms began appearing in southern county apple orchards the week of 5/19 (Figure 2). 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.

Figure 2. Fire blight strike on apple tree branch. Photo by Karlton Neidigh.

Codling Moth: A Codling Moth Biofix was set in Southern counties on 4/28 and in Northern counties on 4/30. 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.

Ambrosia Beetle : Infested trees are showing signs of stress. If you have had a history of this pest in your orchard, now is a good time remove and burn any trees that have been attacked as the flight appears to be declining or is over.

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 forming 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, oil, or oil based penetrants with Captan.

Potato Leafhoppers (PLH): PLH adults began appearing in apples this past week (Figure 3). 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. Neonicotinoids are generally recommended for control however there are other broad spectrum materials that are effective. Refer to the NJ Commercial Tree Fruit Production Guide for more information.

Figure 3. Potato Leafhopper Adult & Nymph

Pear: Second generation pear psylla began hatching about 5/19. Options for control include spinosyn products such as Delegate and Entrust, and the neonicotinoids (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, and Movento. Pear Psylla are still actively laying eggs and nymphs continue to hatch.

Grape: Early blooming native grapes were at trace bloom on 5/16, therefore we have set the Grape Berry Moth biofix at 5/16 for southern counties. Since V. riparia typically blooms with early natives we used Concord 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. 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