Managing Orchards in a No Crop Year: Protecting Tree Health for Next Season
A damaged apple flower cluster at petal fall in Rock Springs, PA, with all fruitlets in the cluster confirmed dead following freeze injury. (Picture Credit: Dr. Shan Kumar)
Weather conditions during winter 2025–2026, along with early spring 2026, have introduced uncertainty about crop potential in Pennsylvania orchards. Chilling requirements for fruit trees were likely satisfied by the time we experienced the January 25-26, 2026, winter storm. The trees remained dormant due to the cold temperatures that persisted from late January through February (Figure 1).
However, many regions of Pennsylvania experienced temperatures below 0°F during this period and, in some cases, negative double-digit temperatures for multiple days. This had a negative impact on the flower buds of stone fruit grown in those regions, resulting in a much lighter bloom this spring. In early March, fruit trees initiated de-acclimation, which was accelerated by the 80°F+ temperatures experienced on March 10. Unfortunately, within ten days, we returned to temperatures in the 20s°F, and this cycle, with varying magnitudes, repeated itself four times, with the last occurring during the April 21 cold snap.
At the time of the April 8 early morning freeze, the majority of the peaches at Biglerville (FREC) were at 80-100% full bloom, and apple varieties were at pink loose cluster (Figure 1). Based on the orchard's elevation, sensors installed inside the blocks recorded 7-8 hours of temperatures below 32°F. Damage assessed after the April 8 cold event was quantified in the Hort blocks, ranging from 33% to 90% kill for peaches (Figure 2) and 3% to 33% in apple blocks (Figure 3).
Across Pennsylvania, similar scenarios repeated, as stone fruit developmental stages at the time of the event ranged from pink bud through petal fall; apple developmental stages ranged from half-inch green to pink, and temperatures ranged from 12-26°F. Common with radiation freezes, there was within-orchard and between-orchard variability driven by elevation, cold air drainage, and site-specific characteristics.
Similar to the April 8 freeze, the April 20-21 freeze event was primarily a radiation freeze, characterized by clear skies, calm winds, and strong radiational cooling overnight. Temperatures dropped to 21-23°F in parts of central Pennsylvania and Bedford County regions, while western, southcentral, and southeastern regions reached 24-29°F. What made this event particularly impactful compared to earlier freezes was its duration: subfreezing temperatures persisted from approximately 11:00 PM on April 20 through 6:00 AM on April 21. Given that most orchards were at full bloom or early post-bloom stages during this freeze event, this prolonged low-temperature exposure likely resulted in varying levels of injury to reproductive tissues. In addition, this event was preceded by a significant stretch of 80-90°F, which may have reduced cold hardiness and could have exacerbated cold-related damage.
Although many weather stations may have recorded temperatures higher than one would expect damage according to the critical temperature tables, there are two things to keep in mind:
- Weather stations can give you an idea; however, temperatures in low-lying fruit blocks will most likely have seen freeze effect issues. Consequently, there was an elevation effect on temperature, which varied from farm to farm. Moreover, the block's topography plays a role; in some instances, cold pockets form, and the cold air lingers, damaging the blossoms.
- The critical temperature tables are not precise, are very old, and were obtained using Red Delicious and older apple varieties. Each variety has a specific level of cold hardiness and a characteristic response to cold. More studies are ongoing to better define those critical temperatures and provide new, more detailed cultivar-specific critical temperature tables for the future
With the potential for reduced fruit set in some blocks across Pennsylvania, there may be a need to shift in management focus toward maintaining tree health and preparing for the 2027 season. This article will cover the critical horticultural, disease, and insect management decisions to consider as we progress into the 2026 season, while keeping future growing seasons in mind.
Horticultural Management
Apples and Pears
The unfortunate spring freeze events may leave many growers in a challenging position, requiring them to make difficult decisions about their apple crop. Before growers make any decisions, individual farm economic evaluation should be done to assess the sustainability of each block. For some, the severe damage may leave the remaining crop load insufficient to justify a full-season crop protection and management program. After such an assessment, it may be decided to remove the remaining fruit to allow the trees to physiologically reset for the following season. In these cases, a 100 – 400 ppm ethephon application can completely eliminate the residual crop. For example, Ethephon 2 SL or Motivate 2 SL at 2-3 pints per acre is a recommended rate. For hard-to-thin varieties, like Fuji and Golden Delicious, a higher rate of 4-6 pints per acre would be adequate. It is recommended to target this application on a hot day with temperatures above 75-80°F to ensure all fruits fall off. There is still time to remove fruitlets, and it can be completed when temperatures are expected to warm up a bit more than the week of April 27 to May 2.
If May and June temperatures are expected to be very warm, prioritizing drip irrigation in the most valuable blocks is strongly recommended. Avoiding excessive tree stress is critical, as drought and heat stress during this period can negatively affect flower bud initiation for the 2027 season.
Flower bud initiation timing varies by cultivar. Honeycrisp initiates flower buds relatively early, beginning roughly 45 days after full bloom (DAFB), whereas Gala is among the latest, often closer to 70 DAFB. High temperatures during the primary flower bud initiation window—approximately 4 to 10 weeks after bloom—have been shown to reduce the number of flowers per cluster in the subsequent season. Research indicates that sustained temperatures around 80°F during this period can contribute to these anomalies. Young orchards are generally more susceptible to this type of heat stress than mature blocks.
In situations where the lack of a crop results in excessive vegetative growth and high vigor, a program of Prohexadione‑calcium (Kudos/Apogee) applications can be considered to suppress shoot extension. A common approach is three consecutive weekly sprays beginning at approximately the 7‑leaf shoot stage, applied at 12 oz per acre per 100 gallons (approximately 250 ppm per application). These applications may be enhanced with an appropriate adjuvant. Reducing vigor improves light penetration within the canopy, which can positively influence flower bud development for the following year.
Root pruning can be used as a vigor management tool, particularly in high-density plantings. It is most effective when applied to actively growing trees, typically from bloom to early summer, and works by temporarily restricting root function to reduce shoot growth and overall vegetative vigor. This response can improve light penetration within the canopy and support return bloom potential in the following season. Under Pennsylvania conditions, root pruning can be incorporated into an integrated vigor management program alongside nutrition adjustments and Prohexadione-calcium applications. Practically, it is done by making a shallow cut in the soil with a root pruner or blade on one or both sides of the tree row, typically 12 to 24 inches from the trunk and at a depth of approximately 6 to 12 inches, depending on soil type and tree size. In Pennsylvania, it should only be used on healthy trees in well-drained soils with adequate soil moisture, as responses are less predictable under drought or other stress conditions.
Once shoot growth has slowed and terminal buds have set, mechanical summer pruning (hedging) may also be considered to help contain canopy growth. This practice should be timed carefully, avoiding very hot or excessively wet conditions, particularly in late July through August, to minimize stress and undesirable regrowth.
Apple Nutrition
Nitrogen management in apple orchards following freeze-induced crop loss should be approached cautiously, with fertilization generally avoided for healthy, vigorous trees. This conservative approach recognizes that when fruit buds or fruit are lost after a freeze, nutrients normally diverted to the developing crop become available for the production of more vegetative shoots and leaves, potentially leading to excessive vegetative growth if nitrogen is applied. However, if trees showed stunted growth the previous year due to severe nitrogen deficiency, applying nitrogen at approximately 30% of the regular rate may be justified to maintain tree health and build adequate nutrient reserves for the following season's crop. The key is to assess tree vigor carefully: healthy trees with good shoot growth do not require fertilization in non-cropping years, as they already have sufficient nutrient reserves stored to support the next season's fruit production.
Stone fruit
If the entire peach crop is lost due to cold damage, the season can be used strategically to adjust and improve canopy structure in the affected blocks. A leaf tissue analysis should be conducted to confirm mineral nutrient status and to guide appropriate adjustments to the ongoing fertility program.
Several studies have evaluated the use of gibberellic acid (GA₃; Falgro, GibGro, ProGibb) applied during flower bud induction to reduce return bloom in the following season. Applications at a rate of 50 ppm, made approximately 85–100 days after anthesis (flower opening or bloom), have shown an inhibitory effect of 40–50% on flowering the subsequent year. This approach can help moderate excessive bloom following a frost year and reduce the risk of over‑cropping, without negatively affecting fruit yield or quality.
Peaches are generally more sensitive to GA₃ applications than nectarines, and the treatment effect tends to be concentrated near the basal portion of the fruiting shoots. As a result, dormant pruning strategies should be carefully adjusted the following winter to avoid removing the sections of the shoots most likely to carry fruit.
Peach Nutrition
For peaches with little to no crop, maintaining 30-50% of the normal nitrogen fertilization rate is essential to ensure adequate reserves are available when trees set a heavy crop the following year. Dr. Rich Marini, Penn State Emeritus Professor of Horticulture, showed that trees that had not been fertilized in a non-crop year showed light green foliage and shorter shoots the following season when they carried a heavy fruit set, demonstrating that some baseline nitrogen application is necessary even without a current crop to maintain tree health and nutrient reserves. For more information, refer to the article on Nitrogen Fertilization of Peach Trees.
Disease Management
Apples and Pears
There are many foliar pathogens that can still be problematic in apple and pear orchards without fruit. Apple scab, rust, powdery mildew, Marssonina blotch, and various leaf spot diseases (e.g., Alternaria leaf spot, Frogeye leaf spot). The goal for 2026 is to prevent defoliation and prevent pathogen buildup. Marssonina blotch severely defoliates apple and pear trees, and it is necessary to continue to control this disease. Petal fall through early June is the time frame when growers need to be actively controlling for Marssonina. A conservative management program is recommended when there is low or no crop present. Growers are encouraged to use broad-spectrum fungicides, such as mancozeb, captan, sulfur, and ziram (if available). Sulfur is the only broad-spectrum product that controls powdery mildew; mancozeb is the only one that controls rust. For the early season (until about second cover), use a tank mix of mancozeb at 3 pounds per acre plus micronized sulfur (8-10 pounds per acre) or wettable sulfur (10-15 pounds per acre). When using mancozeb at the 3 pounds per acre rate, 24 pounds per acre can be applied per season. Since the preharvest interval (77 d PHI) is not a factor when there is no fruit, use mancozeb until the seasonal limit is reached. Then switch to captan (2.5-3 pounds per acre) for the remainder of the season. As an organic option for early-season apple scab and powdery mildew, potassium bicarbonate will help control both. Sulfur will be the best option for Marssonina blotch, as no other effective organic options have been identified to date.
Fire blight can still be a problem this season, especially since we experienced at least two significant infection events during bloom. The freeze did not affect Erwinia amylovora; it may have just slowed it down. The horticultural recommendations for using Prohexadione calcium will not only help control vigor but will also help slow any fire blight that may have occurred in the orchard. In addition, many orchards may experience another flush of bloom due to the recent freeze. These blossoms will be vulnerable, and protection will be necessary if fire blight conditions manifest.
Stone fruit
Bacterial and fungal diseases still need to be managed in stone fruit orchards; however, similar to apples and pears, management can be conservative. Bacterial spot management is necessary since it can also cause premature defoliation. This is the case for susceptible peach, nectarine, plum, and apricot trees. It is recommended that highly susceptible fruit trees without fruit be monitored for disease development on leaves and subsequent defoliation during optimal disease conditions, which are warm (75–85°F), wet, and windy. If disease severity increases during the season, oxytetracycline applications are recommended. Softer products, such as Serenade ASO or Double Nickel, can also be used. Copper products are another option; however, be mindful that they can cause phytotoxicity, especially during wet weather. If we experience a hot, dry summer, the disease's progress will slow. Fungal disease management is still needed to prevent a buildup of rot and leaf pathogens for next season. Using captan at 3 pounds per acre or sulfur (micronized or wettable) at 10-15 pounds per acre will be sufficient to keep the pathogen load in stone fruit orchards in check. This includes limiting powdery mildew, rot fungi, and cherry leaf spot fungi in tart cherry orchards.
Insect Management
It is well known that insect development, as in poikilothermic organisms (aka cold-blooded), is strongly influenced by external conditions. The specific thermoregulation mechanisms help insects to adapt to the deleterious effects of extreme weather conditions. The freeze, which devastated fruit crops across most of the state, did not affect common insect pests. With most or even all fruit damaged, the insects were relatively unaffected and are still developing, looking for food to continue their development.
Unfortunately, if any fruit remains on the tree, insects will find them and continue causing damage. With the lower number of fruit available, each remaining fruit will actually be targeted much more than when plenty of fruit are around. Some insects, such as codling moth, plum curculio, European apple sawfly, or apple maggot, absolutely need fruit for their development, while others, such as leafrollers, aphids, mites, scales, or plant bugs, including brown marmorated stink bug, will also do well in the absence of fruit. Consequently, even if only a small portion of the fruit remains in the orchard and is still intended for harvest, the insect pest management will need to be comprehensive. There are no shortcuts to protecting the remaining fruit from damage. The biggest challenges arise in justifying the economic rationale for insect management practices and in determining optimal timing for treatments.
On the other hand, with no fruit to protect, there is no obvious need to manage direct fruit pests. Pest pressure from species that require fruit for survival should decrease over time and be lower in the next season anyway, even without insecticides. Unfortunately, such conditions will not slow the development of foliar and wood pests. Borers, scales, or aphids can still require specialized treatments. And although there is an almost natural tendency to use the least expensive products, e.g., pyrethroids, which are broad-spectrum and kill most beneficial insects, the season without fruit may present an opportunity to use softer insecticides, such as oils or soaps, to protect trees and support the redevelopment of natural enemies and beneficial insects in the orchard ecosystem. If leafrollers or Japanese beetles become a problem, any Bacillus thuringiensis-based insecticide should provide effective control.
Oriental fruit moth represents a special case: the OFM larvae are direct pests of fruit, but they can easily complete their development in growing peach or apple shoots, and even without fruit, the population can build up and pose a threat to next year's crop. Targeted use of insecticides and/or OFM sprayable mating disruption during the first two flight generations should provide relief from this pest.
Pests such as stink bugs or leafhoppers are not resident pests in the orchard and usually do not overwinter in the orchards, so this year’s control would have only minimal or no impact on the next season’s pest pressure.
Additional Resources
For more information about the phenology of the fruit crop for the 2026 season, please refer to the tree fruit phenology reports:
Penn State 2026–2027 Tree Fruit Production Guide
For commercial fruit growers, please note: When controlling for disease, weather, and tree growth conditions need to be monitored at a local level within one's own orchard. To support management decisions (especially during infection events), growers can use the NEWA website, which has weather stations across Pennsylvania. Before applying chemical products, be sure to comply with current use regulations and read the product label. Product information can easily be obtained from CDMS, Agrian, or Greenbook.
