Metschnikowiaceae

The Metschnikowiaceae family represents a group of yeast-like fungi within the order Saccharomycetales. While many members of this family are recognized for their ecological roles, certain species are significant plant pathogens capable of causing substantial damage to agricultural crops. They are particularly noted for their ability to thrive in high-sugar environments, such as ripening fruits and berries.

These pathogens primarily target grapevines, pomaceous fruits, and soft fruits. The damage caused by Metschnikowiaceae is frequently associated with pre-harvest fruit rots. Once the fungus enters the host tissue, it accelerates the degradation of plant cell walls, leading to rapid tissue collapse and significant yield losses for growers.

Symptoms of an infection often include soft, watery lesions that may develop a visible, light-colored yeast-like growth. The tissue frequently becomes fermented, emitting a characteristic odor that indicates the activity of these microorganisms. As the disease progresses, the fruit loses its structural integrity, making it susceptible to secondary bacterial and fungal infections.

The development and spread of these fungi are highly dependent on environmental conditions, specifically humidity and temperature. Optimal growth occurs in warm, moist weather, especially when fruit skins are compromised by physical damage, bird pecking, or insect activity. These wounds act as entry points for the fungi to colonize the interior of the fruit.

Management and prevention require an integrated agronomic approach:

• maintaining orchard and vineyard hygiene to reduce initial inoculum;
• controlling insect pests that damage fruit integrity;
• implementing proper canopy management to ensure air circulation and reduce humidity;
• applying appropriate fungicides or biological control agents when conditions favor infection.

Strict monitoring during the late ripening stages is essential to identify early signs of rot. By managing environmental factors and minimizing physical injuries to crops, producers can effectively limit the impact of Metschnikowiaceae and ensure a healthier, more profitable harvest.