Rutgers Tree Fruit IPM Report for July 1, 2023

Peach:

Oriental Fruit Moth: A biofix point for OFM was set on 4/10 in both northern and southern counties.  All timings for first generation OFM have past. Third generation timings are updated below:

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

Thrips: Flower Thrips have caused slight damage on highly colored ripening fruit, especially in poorly managed ground covers that contain clover or other flowering weeds. The current weather pattern has turned to unfavorable for thrips but they still may cause some damage. Thrips damage appears as “silvering” and usually appears on fruit close to harvest. If populations are high damage can be extensive. Presence of thrips may be scouted for using a beating tray to detect the presence of adults and nymphs in the tree. Flowering weeeds and shrubs on orchard edges may also be scouted by shaking flowers onto a beating tray or a sheet of paper. Delegate or Entrust at the highest labeled rate are the usual recommended materials for thrips in stone fruit. Lannate may be effective in some orchards but has not worked well in recent years. These materials all have short PHI’s and may be applied close to harvest when damage typically appears. See the NJ Commercial Tree Fruit Production Guide for more information.

Apples and Pears:

Diseases: Now that primary scab 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 and Inspire Super 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.

Fire Blight: Fire Blight symptoms began appearing in southern county apple and pear orchards the week of 5/1. 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. In southern counties terminal buds have set in most varieties. It should be safe to start cutting out blighted wood however this should be done during dry weather.

Codling Moth (CM): The first generation codling moth timings have ended. Trap captures continue and decreased in most southern county orchards this week. A biofix was set for CM on April 17^th in both northern and southern counties. Second generation timings are updated below. Rimon is not recommended for this and later generations.

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.

Wooly Apple Aphid (WAA); Green Apple (Spirea) Aphids (GAA): GAA colonies are present in most 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. Wooly apple aphids are also appearing, and are building up in some southern county orchards. 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. Both materials will suppress scale at this time. Do not combine Diazinon with Captan.

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 50% bloom on 5/24, therefore we have set the the Grape Berry Moth biofix at 5/24 for southern counties. Typically we would use the bloom date for V. riparia to set the biofix date, however the usual locations we have used in the past did not have viable vines to look at, and it is difficult to scout new locations for V. riparia this year. 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 735 DD in southern counties. Applications have been historically made around the end of June in southern counties.

Powdery Mildew (PM):  PM symptoms began appearing on berries and rachises this past week in several vineyards. Options for eradication or suppression of established infections are limited. Sulfur, Oxidate, potassium bicarbonate products, and mineral oils are most often recommended. Note that sulfur should be used with care and avoided on sulfur sensitive varieties. Sulfur or Captan should never be combined with or used within 2 weeks of oil applications.

Tree Fruit Trap Captures – Southern Counties

Tree Fruit Trap Captures – Northern Counties

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