Russeting of apple fruits

Russeting, often referred to as rough skin, is a common physiological disorder affecting apple fruits. It is characterized by the formation of brown, corky, or net-like tissue on the surface of the fruit skin, which detracts from its aesthetic appeal and market value.

The primary symptom is the localized or uniform development of rough, matte patches on the apple skin. Unlike fungal infections, this condition results from the rapid expansion of fruit cells combined with environmental stress, causing the cuticle to crack and subsequently produce a suberized protective layer.

Environmental conditions are the main drivers of this disorder, particularly during the cell division phase shortly after petal fall. Factors such as high relative humidity, prolonged periods of rain, and significant fluctuations in temperature can trigger the formation of russeting in susceptible apple varieties.

While russeted apples are still edible and often retain their flavor profile, they suffer from reduced commercial quality. They are prone to excessive water loss during post-harvest storage, leading to shriveling, and fail to meet the stringent cosmetic standards required for fresh fruit markets.

Preventive strategies focus on mitigating plant stress and managing the growing environment. Key practices include:

• selecting resistant cultivars for cultivation;
• carefully timing chemical applications to avoid phytotoxic stress;
• optimizing irrigation and nutrient programs, especially calcium supplementation;
• maintaining good orchard ventilation to manage humidity.