Shot hole disease: how to protect stone fruit and preserve premium fruit prices

Spring has made one thing unmistakably clear: the stone fruit season will be defined by price. Tight supply and the mounting risk of weather-related losses are setting the stage for elevated prices for apricots, peaches, sweet cherries and plums. Yet at the same time, the market is becoming markedly less tolerant of quality flaws. In this environment, protecting orchards from shot hole disease is no longer merely a phytosanitary concern — it is a matter of economic survival, writes EastFruit.

In comments to Agrotimes, Dmytro Tymoshenko, Technical Support Manager for Specialty Crops and Grapes at Syngenta, stresses that shot hole disease remains one of the most destructive threats to stone fruit production, capable of significantly undermining both marketability and sugar accumulation in fruit.

A deceptively simple name, a complex threat

Caused by the fungus Clasterosporium carpophilum, shot hole disease affects all stone fruit species. Although commonly associated with the characteristic perforations it creates in leaves, the pathogen’s reach extends far beyond foliage. It attacks shoots, buds, branches, fruit set and the fruit itself.

Typical symptoms include:

• small, round lesions that drop out of leaves, leaving a “shot hole” appearance;

• cankers on shoots accompanied by gum exudation;

• brown to purplish spots on fruit that expand and eventually crack.

These cracks are more than cosmetic defects. They reduce sugar content, compromise visual appeal and create entry points for secondary infections such as fruit rots. In premium market segments, even minor blemishes can translate into meaningful price discounts.

Why 2025 heightens the pressure

The pathogen is active at surprisingly low temperatures. Conidia begin forming at just +4°C, and under humid, windy conditions infection can spread rapidly throughout an orchard. With a short incubation period and the capacity to produce multiple generations within a single season, the disease can escalate quickly if control measures are delayed.

“Effective protection begins with pruning,” Tymoshenko notes. “This reduces the infectious load, as the pathogen overwinters on infected bark and fallen leaves.”

Building a resilient protection strategy

A successful program relies on timing, prevention and consistency.

Sanitary measures
The foundation lies in removing sources of inoculum: pruning infected branches, eliminating plant debris and reducing overwintering infection reservoirs.

Early spring protection
Applications of copper-based products help suppress both fungal and bacterial pathogens at the outset of the season.

Pre-bloom stage
Horus® (0.3 kg/ha) is recommended before flowering. According to trials conducted by the Ukrainian Plant Quarantine Research Station, even a single application at this rate achieved 78.3% efficacy, outperforming comparable alternatives.

Full bloom (BBCH 65)
Switch® (1.0 kg/ha) is considered particularly effective during peak flowering, when shot hole disease often coincides with blossom blight (Monilinia spp.) and overall disease pressure intensifies.

Post-bloom period
Miravis® (0.5 l/ha) offers translaminar activity and extended protection of at least 14 days. As an SDHI fungicide, it is best used preventively; where curative action is required, combining with a triazole product can enhance flexibility and efficacy.

Fruit development stage
Subsequent waves of infection should be managed with contact fungicides or mixtures. Switch® or Horus® may be used during fruit growth, with careful attention to pre-harvest intervals, to protect against both shot hole disease and fruit rots while minimizing deformities and cracking.

The financial calculus

In a high-price year, the cost of inaction can be steep. Fruit affected by shot hole disease often:

• loses visual appeal and grading potential;

• demonstrates reduced storage performance;

• commands lower prices;

• or is rejected outright.

In that context, fungicide programs should be viewed not as an operational expense but as a strategic investment in preserving margins.

“Protection against shot hole disease forms the backbone of fungicide programs in stone fruit,” Tymoshenko concludes. “It requires expertise and resources, but it ultimately pays for itself through quality yield and stronger returns.”