Flyspeck of apple

Flyspeck of apple is a fungal disease caused by the pathogen Phyllachora pomigena (often associated with Schizothyrium pomi). It is classified as a superficial blemish disease, meaning the infection does not penetrate the flesh of the fruit but significantly affects its external appearance.

The primary host for this fungus is the apple tree. The disease typically becomes evident during the latter part of the growing season as fruits begin to mature, particularly in regions with high humidity and abundant rainfall during the summer months.

Symptoms are easily identified by the presence of small, discrete, shiny black spots on the apple skin, which resemble fly specks. These spots can occur singly or in large clusters, sometimes appearing in conjunction with a diffuse, cloudy, or brownish discoloration of the cuticle.

The disease thrives under conditions of high relative humidity and moderate temperatures. Orchards with poor airflow, dense canopies, or those located in low-lying areas with morning dew or fog are significantly more susceptible to outbreaks, as these factors keep the fruit surface moist for extended periods.

The economic impact of flyspeck is primarily related to the loss of market quality. Although the infected fruit remains edible and the interior is unaffected, the cosmetic damage results in downgrading the crop, leading to substantial financial losses for commercial apple growers who target fresh market standards.

Integrated management practices include:

• Pruning trees to improve air circulation and canopy light penetration.
• Thinning of the fruit load to prevent contact between apples, which can trap moisture.
• Applying preventive fungicides during the summer months when infection pressure is high.
• Removing debris and managing weeds to reduce the overall humidity within the orchard floor.