Shot hole disease

The fungus is capable of overwintering as mycelium in infected branches, buds, and gummosis lesions excreted by the plant.

During the growing season, the pathogen spreads through conidia, which are dispersed by wind, rain splashes, and insects.

The infection mainly affects stone fruit crops, including cherries, plums, apricots, peaches, nectarines, and almonds.

The pathogen can attack all aerial parts of the plant, including leaves, fruits, buds, flowers, and young shoots.

The first sign of the disease on leaves is the appearance of small, circular, reddish-brown spots with a lighter center.

Over time, the tissue in the center of the spot dies and drops out, which gives the disease its common name: shot hole disease.

On young shoots, reddish-purple lesions form, which expand over time and cause the bark to crack.

Fruit infection manifests as small, depressed spots, often accompanied by the exudation of gum (gummosis).

If the infection is severe, flowers become deformed, dry out, and drop off en masse, leading to significant yield loss.

The development of the fungus is favored by moist and moderately warm weather typical of spring and early summer.

For conidia germination, liquid moisture is required for several hours, along with temperatures ranging from 10 to 25 degrees Celsius.

Frequent rain and fog create ideal conditions for the rapid spread of spores and re-infection of healthy plant tissues.

Excessive density of the tree canopy prevents airflow and promotes long-term moisture retention, triggering disease outbreaks.

Poor orchard maintenance and the presence of numerous dead or infected branches serve as an infection reservoir.

Shot hole disease significantly reduces orchard productivity through premature leaf fall and damage to reproductive organs.

Shoot damage leads to dieback and overall weakening of the tree, making it susceptible to other pathogens and frost injury.

The market value of fruit is compromised due to spotting and gummosis, making the harvest unsuitable for commercial sale.

Without systematic treatment, trees may die within a few seasons due to chronic exhaustion and stress.

The disease negatively impacts the formation of fruit buds for the following year, leading to irregular or biennial bearing.

The primary control measure is timely pruning and removal of infected shoots, which act as a source of inoculum.

It is important to regularly whitewash trunks and scaffold branches to prevent bark cracking and winter injury.

In autumn and early spring, it is recommended to apply eradicant sprays using copper-based fungicides or iron preparations.

During the growing season, as soon as the first symptoms appear, systemic fungicides should be applied according to the label instructions.

• Consistent irrigation and fertilization to improve tree immunity.
• Collection and destruction of fallen leaves in autumn.
• Proper spacing during planting to improve canopy ventilation.