April 14, 2026 , and

Fire blight infection predicted week of April 13

NEWA is predicting a high risk for fire blight infection this week as a result of favorable conditions for apple orchards in bloom. Favorable conditions include 1) a certain number of heat units accumulated during bloom for a threshold level of inoculum to be reached; 2) a wetting event to wash the bacteria into infection sites; and 3) the average temperature is above 60°F. If at least two conditions are met during bloom, then the risk for infection is ‘High’ and antibiotics should be applied. A wetting event is not necessary to elevate the risk. Additionally, forecasted wetting events should be carefully considered and a bactericide applied just before or after a rain event.

When using the fire blight model on NEWA, it is important to enter your own “First Blossom Open Date” for your orchard as this can drastically change predictions. You can also enter your orchard’s history with fireblight in the first drop down menu. Lastly, you can enter the date you last applied an antibiotic this season and the model will reset to provide the most accurate predictions. When using the model, it is important to look at the column farthest to the right in the chart titled “Infection Potential EIP Value” since this is the most accurate prediction for our region. Any time the model shows an orange (High) or red (Extreme) output and the value for that date is above 100, an antibiotic application is warranted.

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 only allows for 1 postbloom 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 or other plant defense elicitors may improve control. Applications of Apogee or Kudos during bloom can work to prevent shoot blight after petal fall. The use of Actigard and Apogee are especially recommended in new plantings where instances of shoot blight can kill young trees. For further recommendations on these products, Michigan State University published a guide including information on application timing and product rates.

Additionally, for peaches at petal fall, copper formulations should be used to suppress bacterial spot. Generally we recommend starting at 0.5 oz of metallic copper and gradually lowering the rate as the season progresses. The rate applied will depend on the formulation. Dr. Norm 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 such as Mycoshield or Fireline may also be used and may offer slightly more residual activity during long wetting periods.

Filed Under: Fruit, Tree Fruit, Uncategorized Tagged With: , , , ,
April 10, 2026

Assessing the Severity of Frost Damage to Peach and Apple Flower Buds

Figure 1. The brown and shrunken pistil (L) indicates the flower is dead; a green and upright pistil indicates that the flower is alive. Photo by H. Gohil.

The below-freezing temperatures on Wednesday (4/8/26) and Thursday (4/9/26) early mornings are likely to cause frost damage in several peach and a few apple orchards in New Jersey. It got down to 25°F–28°F in Southern NJ, and 22°F -27°F in Central and Northern NJ, and those temperatures could have killed vulnerable blossoms. The night of April 8th saw wind speeds above 10 mph, which mixed the cold air at the bottom with the warm air above. This prevented cold-air stratification and reduced the heat loss from the soil surface and plant tissues. The night of April 9th was even colder, and the wind dropped below 5 mph, almost coming to a standstill for a few hours. This causes the rapid loss of thermal energy from the soil and plant tissues. Most unprotected peach and a few apple orchards were affected by these conditions on the night of April 9th. In several parts of New Jersey, peach flower buds were at full bloom, the most susceptible stage to frost (Fig. 1). In Apples, though most orchards were in the tight cluster or earlier stages of bud development, and few varieties were in the first pink. The critical temperatures for 90% bud kill at these stages are 21°F for the tight cluster and 24°F for the first pink; hence, only a few apple orchards in South NJ were vulnerable to significant frost damage (Fig. 2).

Figure 2. Frost damage to Apple bloom at first pink

In Peach, not all flowers bloom at the same time, which makes frost-damage assessment a little more difficult. Often, many flowers look damaged, but they still bear fruit. This estimate can be even more difficult in some varieties, simply because they bloom so much that even 90% damage can yield close to the full crop. The natural tendency is to look for open flowers, which can easily lead to overestimating the damage. The developing flower buds will quickly die once damaged by a freeze. You can’t tell what will happen just by looking at the flower. The browning of flower petals doesn’t mean the ovary is dead.

You can do a quick, destructive assessment of loss by randomly opening 10-20 flowers per tree; do this on 5-10 trees across an acre or block for each variety. This can give a relative estimate of bloom loss. If you take a more systemic approach, you may get more accurate results. Due to cold-air stratification, cold air settles to the bottom, so more buds are damaged at the bottom; therefore, you want to sample from both the upper and lower branches. Sometimes, the loss of flower buds could be as good as natural thinning. So, flower bud loss may not result in a crop loss.

After opening the flower, if the pistil is shrunken and brown, consider it dead; and if completely green, consider it alive (Fig 1). The pistil is sticking out, and you see it is brown; it could have been pollinated and is in the senescence stage. It is not brown because of frost, but it’s brown because of the normal progression of development. In another scenario, the pistil is brown because it has frost damage, but it still may have done its job of pollination. It served its purpose and senescence because both frost and pollination are over. After pollination and fertilization, rapid hormonal changes enhance fruit development and make them slightly more cold-hardy. So even the destructive analysis is a close approximation.

Figure 3. Uneven development of peach due to frost injuries, represented by very small ripe fruits in PF Flamin Fury 24 (Left) and Silverglo (right), and a significant number of green unripe fruits in Lady Nancy (middle). Photo by H. Gohil.

If frost occurs at the shuck-split or shuck-off stage, the seed/pit will be damaged. But the fruit looks normal. However, they will not reach full size because the nonviable seed cannot produce the hormones required for fruit growth (Fig. 3). Even if they do grow, they may still face other problems. For example, the pit may have sustained damage, predisposing it to shatter during phase III of fruit growth. If you wait for a week to 10 days, it will be easier and more accurate non-destructive assessment. The live flowers will develop normally, and the dead flowers will be shrunken brown mummies that can be flicked away easily. You will still have plenty of time to adjust fruit thinning to achieve a near-normal crop. You should not be in a hurry to do fruit thinning this year! If you see some fruits that have stopped getting bigger and are distinctly smaller, will you want to thin? Maybe after the June drop.

Filed Under: Blueberry, Cranberry, Fruit, Strawberry, Tree Fruit, Wine Grape Tagged With: , , ,
March 27, 2026 , and

Fruit IPM Updates Week of 3/23/26

Tree Fruit Phenology Update

Tree fruit phenology is progressing across New Jersey, with development in southern counties remaining slightly advanced and northern regions beginning to catch up. Overall, the 2026 season is showing a more compressed phenology window than typical. Cooler weather this weekend should help slow development.

In apples, green tip for Pink Lady was observed around March 22 across both southern and some northern regions, with Honeycrisp following around March 26. In pears, swollen buds were observed around March 11, with green clusters reaching by March 26 in southern New Jersey. Peach varieties in southern New Jersey were observed at the swollen bud stage this week.

Apples
Green Tip Dates by County
County Green Tip Date (earliest varieties) 
Cumberland 3/22
Gloucester 3/22
Burlington 3/22
Mercer 3/22
Middlesex 3/22
Monmouth 3/22
Hunterdon 3/22
Morris TBD
Warren TBD
Sussex TBD
Bergen TBD
Apple Scab
Models

Apple scab models are available through NEWA and RIMpro. Apply fungicides before infection events when discharge exceeds thresholds (10–20%).

Current Update
  • ~2% ascospore maturity (March 25)
  • ~7% by March 31
  • ~10% by April 1
  • Low cumulative discharge (~1–4%)
Management Considerations

Copper can be applied now but avoid after ½” green.

  • Manzate + single-site fungicide
  • DMI (FRAC 3) for high pressure
  • Vangard (FRAC 9)
  • FRAC 7 (save Aprovia)
  • Axios (save for later)
  • Syllit (avoid if resistance)
  • FRAC 11 (save for summer)
  • Topsin (limited uses)

As we move toward tight cluster:

  • Rapid ascospore increase
  • Higher infection risk with rain

Monitor:

  • NEWA models
  • Weather/wetting events
  • Phenology

Early control is critical to avoid season-long pressure.

Scouting Calendar

Use as a scouting guide only (not for spray timing).

  • Green tip: March 22–26
  • Ascospore maturity: 2–7% increasing
Key Points
  • Minimal difference between North and South Jersey
  • Green tip ~March 22
  • Prepare for scab infection events
  • Build fungicide rotation now

Pears
Pear Phenology Update

Pear phenology is progressing, with swollen buds observed around March 11 and green clusters observed on March 26 in southern New Jersey.

Pear Psylla

Pear psylla activity has begun in southern New Jersey, with variability across counties:

  • Salem County: adults and eggs observed
  • Gloucester County: eggs observed
  • Burlington County: no activity observed to date

These observations indicate that egg laying is underway in the southernmost regions and will likely progress north with warming temperatures. Reports from surrounding regions also suggest psylla activity is increasing.

At this stage:

  • Continue monitoring for eggs and early nymphs
  • Use beating trays to assess adult activity
  • Examine buds and developing shoots for egg presence

Dormant oil applications should be applied where possible to deter psylla egg laying and suppress early populations. Timely applications are especially important in areas where activity has already been observed.

At green cluster:

  • Oil is often combined with an insecticide to target migrating adults
  • In lieu of oil, particle films such as Surround may be used starting at swollen bud and continuing through bloom

Materials such as Esteem, Centaur, and Sivanto Prime may also be incorporated, depending on timing and pressure.

Adult pear psylla laying eggs.

Figure 1. Adult pear psylla laying eggs at swollen bud. Photo by Janine Spies.

Pear Diseases
Fire Blight and Early Season Management

Dormant copper applications should be applied for fire blight and pear scab suppression, but no later than green tip if fruit russet is a concern. Where copper has already been applied, early-season risk is likely reduced.

As bloom approaches:

  • Begin planning for antibiotic applications
  • Kasumin may be used at bloom and petal fall
  • Other options include streptomycin and oxytetracycline for post-bloom use

Rotating chemistries is important for resistance management.

Pear Scab

RIMpro modeling for pear scab in Upper Deerfield indicates low infection risk at this time, with infection values remaining below threshold levels. Despite recent wetting events, limited ascospore maturity is restricting infection potential.

Growers who have applied dormant copper are likely adequately protected under current conditions. Protective fungicide programs should begin at the cluster bud stage, particularly as we approach tighter cluster and bloom, when risk will increase.

Materials such as Ziram or EBDC formulations provide effective protection. At white bud, include materials effective against pear scab, rust diseases, and Fabraea leaf spot. Particular attention should be paid to rust on Asian pear varieties.

Dormant urea applications may also be used, where appropriate, to help reduce overwintering inoculum.

Summary
  • Pear psylla activity has begun in southern New Jersey, with adults and eggs observed in Salem County and eggs in Gloucester County
  • Dormant oil applications should be applied to suppress egg laying and early populations
  • Copper applications should be completed by green tip where russet is a concern
  • Pear scab risk is currently low based on RIMpro modeling
  • Fungicide programs for pear scab should begin at cluster bud as risk increases
  • Dormant urea may be used to reduce overwintering inoculum

Continued scouting will be important over the next 1–2 weeks as both insect and disease pressure increase with advancing phenology.

Peaches

Peach Phenology

Peach varieties in southern New Jersey were observed at the swollen bud stage this week. Development is progressing steadily and will advance with warming temperatures.

Peach Swollen Bud

Figure 2. Peach Swollen Bud. Photo by Janine Spies.

Brown Rot

Blossom infections from the brown rot fungus can occur whenever pistils are exposed and favorable environmental conditions are present.

Infections can occur during any wetting period when temperatures are between 41 and 86°F. Optimum conditions occur with wetting and temperatures in the mid-70s. During extended wetting periods (several days or more), blossoms can be infected regardless of temperature. Infections under suboptimal conditions are generally less severe.

Blossoms and fruitlets remain susceptible until the pistil desiccates, which occurs sometime between petal fall and shuck split.

Initiate coverage for blossom blight starting at pink for short-petaled varieties and at 5–10% bloom for showy flowers. Refer to the NJ Commercial Tree Fruit Production Guide for recommended materials and rates.

Scale Insects

Oil applications may be safely applied up to pink on peach.

Oil can be applied alone or in combination with insecticides including Centaur, Sivanto Prime, and Esteem.

Filed Under: Commercial Ag Updates, Disease Forecasting, Fruit, Tree Fruit, Uncategorized Tagged With: , , , , , , , , ,
April 5, 2025

High Risk of Frost Damage in Peach Orchards

The below-freezing temperatures on Tuesday (4/8) and Wednesday (8/9) will likely invite frost damage to peach orchards in New Jersey. In several parts of New Jersey, peach flower buds are in the bud swell to the petal fall stage.

Figure 1. Peach bud development stages and corresponding critical temperatures. Adapted from MSU Fruit Extension. Photos by H. Gohil

Bloom progression in southern New Jersey indicates that except for very few delayed blooming varieties such as ‘Gloria’ and “Scarlet Rose’ most varieties will be in the bloom or post-bloom, next week. These are the most vulnerable stages to frost damage (Figure 1). Often, the cause is a few hours below the injury threshold temperature for the developing buds. Monitoring the growth stage and weather conditions will help in determining the actual threat of frost damage and whether to start a frost protection system.

Monitor the orchard temperature. Frost can occur when the ambient temperature dips below freezing (32°F). The hourly falling rate and the lowest forecasted temperature should also be monitored.  Because the threshold temperature for each bud development stage is different, and a slight temperature difference can make a difference between frost damage and no damage, it is essential to know the precise temperature. In most cases, the orchard temperature will not be the same as forecasted or reported by the weather channels because the weather station could be farther away than the orchard location. Remember that the nighttime temperatures often dip below the predicted temperatures. It is crucial to have a thermometer in the orchard. Even the data from the nearby weather station could be unreliable. Also, frost alarm systems can give precise temperatures in the orchard and send warning messages to your mobile phone at a set temperature. Some systems can also report wet-bulb temperature, essential when using overhead irrigation for frost protection (Figure 2).

Monitor the bud development stage for each variety block, starting from bud swell. Critical temperatures have been researched and calculated for each bud development stage. For example, at 25°F, a peach orchard in full bloom can expect up to 90% crop loss, but at the first pink stage, it will suffer only marginal loss (Figure 1).

The critical temperature for damage at a particular bud stage may vary by 4-5°F depending on temperatures during the previous few days before the cold event.

Figure 2. Weather Station with in-built frost alarm system in Peach Orchard, Medford, Southern NJ.

Therefore, growers should use caution when using these published critical temperatures for active frost protection methods. Also, knowing the bud development stage for all varieties in the orchard will allow you to prioritize varieties or blocks that need frost protection.

Cloud coverage:  Clear skies enhance radiative heat loss into the sky, which results in lower temperatures than when there is cloud cover, which can trap radiant energy from the ground.

Wind Speed: Wind increases the rate of heat loss from the ground and plant tissues. Low speed allows the formation of the inversion layer. Most frost protection methods will have reduced efficiency at wind speeds above 10 mph. Fire or heat application-based methods are less effective at wind speeds below five mph.

The frost protection method should only be employed after determining the actual risk of frost and considering the cost-benefit analysis. The articles below have information on passive and active frost protection methods.

Filed Under: Blueberry, Cranberry, Fruit, Strawberry, Tree Fruit, vegetable, Wine Grape Tagged With: , , , ,
February 27, 2024

Early Season Tree Fruit Pest Control for 2024

  • Dormant season oil sprays
  • Dormant season copper sprays
  • Dormant season urea sprays

[Read more…]

Filed Under: Tree Fruit Tagged With: , , , , , , ,
April 17, 2023 and

Tree Fruit IPM Report for April 18, 2023

Tree Fruit Phenology: Tree Fruit Phenology remains advanced in peach, but development is slowing. In southern counties all peach orchards are late bloom to petal fall. Redhaven was at approximately full bloom on April 4. 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. [Read more…]

Filed Under: Tree Fruit, Wine Grape Tagged With: , , , , ,