Tree Fruit IPM Report for April 24, 2024

Tree Fruit Phenology: Tree fruit phenology has slowed. In southern counties all peach orchards are petal fall to shuck split. Redhaven /PF-17 was at approximately full bloom on April 5. Plums are at shuck off. Pears are at petal fall. Red Delicious is just past full bloom. Sweet cherries are at about late bloom depending on variety.

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.

Peach Scab: In addition to Rusty Spot and Bacterial Spot, Peach Scab requires protective applications starting at petal fall. Peach scab cankers begin to expand at bloom and by shuck split begin to shed spores during wetting periods. Topsin, Topsin/Captan combinations, Flint Extra, Inspire Super, and especially Quadris Top applied at petal fall are the best materials for blocks that had scab last year. Quadris Top, Flint Extra or Topsin should be used at the high rate to suppress overwintering lesions on the wood. Quadris Top contains azoxystrobin which is phytotoxic to many apple varieties. Phytotoxic residues can remain in the tank for long periods after an application is made, even if a tank cleaner is used. Do not use Quadris Top or Abound in the same sprayer used for apples. Bravo (chlorothalonil) is also a good protectant that may be applied no later than shuck split. Captan is also helpful in cover sprays after shuck split where scab was troublesome last year.

Oriental Fruit Moth: A biofix point for OFM was set on 4/10 in both northern and southern counties.  The first of two insecticide timings for first generation Oriental Fruit Moth control fall at 170-200 degree days base 45 after biofix. This timing generally coincides with 100% petal fall in peaches. Timings are updated below: Note that timings have been pushed back from last week due to cooler than forecast weather. Do not apply insecticides until all bloom is off. No Insecticides for OFM are needed where Mating Disruption is implemented.

Green Peach Aphid: GPA colonies begin forming sometime during bloom. Examine trees for the presence of colonies from pink to shuck split. Count the number of colonies on ten trees and use a treatment threshold of 2 colonies/tree at petal fall for peach, and 1 colony/tree for nectarine. The best way to scout for aphids during bloom is with a beating tray. Blossoms may also be collected, opened, and examined for the presence of aphids using a hand lens. This is particularly important for nectarine blocks. Check 10 trees per block with the beating tray. Collect 50 blossoms per block and examine for the presence of aphids. If more than 1 colony of aphids are found in nectarines, or 2-3 colonies are found in peaches, an insecticide for aphids will be needed when all petals are off. See the NJ Commercial Tree Fruit Production Guide for recommended materials and rates. The first aphid activity was noted in southern counties last week.

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 168 DD base 50 in southern counties, and 109 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. Catfacing insects are starting activity but cause little damage at this time of the year. Catfacing insects will become more of an issue as temperatures warm and mowing and other ground cover activities become more common after bloom. Insecticides for catfacing insects are not recommended until after all petals are off.

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 shuck split 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 green peach aphid when used at this timing.

Lesser and Greater Peach Tree Borers: Growers using mating disruption for borer control can begin placing dispensers around the end of April and should have them in place by mid-May.

Apples and Pears:

Diseases: Fire Blight, Apple Scab, Rust diseases, and Powdery Mildew are the main targets at this stage. The NEWA apple scab model is estimating about 88% ascospore maturity as of 4/22 in southern NJ with 83% of cumulative ascospores discharged. The model estimates about 69% ascopsore maturity for Northern Counties with 43% ascospores released. Primary apple scab spores are released during any substantial infection period. Between tight cluster and first cover include products effective  for powdery mildew and cedar apple rust. To manage Fire Blight in both apples and pears, consider using Kasumin at bloom. Kasumin is an antibiotic like Streptomycin and Oxytetratracycline. It contains Kasugamycin which is a different chemistry. Kasumin is only labeled for bloom and petal fall applications while strep and oxytet are labeled for post bloom use (Note that Fireline 45 is only labeled for 1 post bloom application on apple.). Using 3 different chemistries in rotation allows for resistance management while extending the protection into the post bloom period when late blossoms typically appear which ever material you use, the addition of Actigard, Lifegard, or other plant defense elicitors may improve control.

Rust Diseases: The two most common rust diseases that affect pome fruit are Quince Rust and Cedar Apple Rust. In some years these diseases can be troublesome in commercial orchards. Most disease control programs for scab will also control rust. In organically managed blocks in the east options are limited for approved materials that are effective for rust. Potassium Bicarbonate products have shown good efficacy for rust diseases in trials performed in Virginia. Organic growers should seek out and plant rust resistant cultivars. Cultural controls are not practicable due to the widespread presence of alternate host Junipers both wild and cultivated. Rust disease development on junipers should now be producing large spore releases during wetting periods. See this link for pictures of rust on pome fruit and juniper.

Codling Moth: A Codling Moth Biofix was set in Southern counties on 4/22. 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.

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 shuck split 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 1st generation pear psylla when applied at petal fall.

Rosy Apple Aphid:  If a pre-bloom application was not made, monitor for colonies during bloom and use a treatment threshold of 1 colony/tree at petal fall.

Ambrosia Beetle: This pest has traditionally been an economically damaging pest of ornamental crops. In more recent years we have found it opportunistically attacking our tree fruit orchards. Ambrosia Beetles are attracted to young, stressed trees with trunks no greater than 4 inches in diameter, however it will attack larger trees in some years. Over the past few years, some New Jersey farms have experienced significant tree loss to this pest. In northern counties we are been experimenting with Ambrosia Beetle monitoring tools. Each farm in the program has had one clear sticky trap with a commercial ethanol lure and three wood dowel traps filled with ethyl alcohol placed along the wood line closest to their tree fruit orchards. The clear sticky trap is being used to monitor flights of this pest while the wood dowel traps are being used to time management decisions. We had our first Ambrosia Beetle trap catch on 4/8, since then this pest has been caught on the clear sticky traps at every location they were placed at. We had our first damage to the wood dowel traps on 4/18 so we can expect to see these beetles becoming an issue in orchards where they have historically attacked relatively soon. Indeed we have seen tunneling in southern county orchards this past week.

Pear Psylla:  Dormant oil applications should have already been started to deter psylla egg laying. At the green cluster stage a pyrethroid or Esteem is generally included with oil. Pyrethroids may knock down some of the adults migrating into the orchard, while Esteem may sterilize them.  In lieu of oil or insecticides, Surround may also be applied starting at swollen bud and continued through petal fall. If using Surround through the bloom period stop at petal fall and switch to applications of 1% summer oil @ 1gal/100 in no less than 150 gals/ac. these should be made at no more than 2 week intervals. At petal fall insecticide options for Psylla control include Actara, Assail, Belay, Movento, Sivanto Prime, and Agri-mek. See the NJ Commercial Tree Fruit Production Guide for recommended materials and rates.

Pear Diseases:  Include effective materials such as Ziram or EBDC formulations for Pear Scab and Rust diseases beginning at the cluster bud stage. At white bud use products effective for pear scab, rusts, and fabrea leaf spot. For both apples and pears, consider using Kasumin at bloom. Kasumin is an antibiotic like Streptomycin and Oxytetratracycline. It contains Kasugamycin which is a different chemistry. Kasumin is only labeled for bloom and petal fall applications while strep and oxytetracycline are labeled for post bloom use. Using 3 different chemistries in rotation allows for resistance management while extending the protection into the post bloom period when late blossoms typically appear. Whichever material you use, the addition of Actigard, Lifegard, or other plant defense elicitors may improve control.

Grapes: Grapes are at budbreak to the 3″ stage of development. The most important disease to manage at this time is Phomopsis. Insect pests to monitor are Grape Flea Beetle, and Climbing Cutworms. Controls for these insects are rarely needed. If control is determined to be necessary, use one of the materials recommended in the New Jersey Commercial Grape Production Guide. It’s also not too late to scout for and destroy SLF egg masses on posts and trunks.

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

Tree Fruit Trap Captures – Southern Counties

Tree Fruit Trap Captures – Northern Counties