Strawberry anthracnose

Strawberry anthracnose is a severe fungal disease caused by the pathogen Colletotrichum acutatum. This disease affects various parts of the strawberry plant, including stems, leaves, flowers, and fruits, often resulting in significant economic losses for commercial growers and home gardeners alike.

The disease primarily targets cultivated strawberries. It is a highly persistent pathogen that can survive in soil, on infected plant debris, and on asymptomatic host plants. Because the fungus is highly mobile, it can spread rapidly across a field during periods of high humidity or rainfall.

Symptoms typically start as small, water-soaked lesions that quickly become dark, sunken, and necrotic. On fruits, these lesions appear as circular, depressed spots that eventually develop a characteristic salmon-colored mass of spores. Infected flowers often wither and die, and the disease can cause lesions on petioles and stolons, weakening the plant structure.

Environmental conditions are the primary drivers of the disease, with warm temperatures ranging from 20°C to 30°C and persistent moisture being the most favorable for spore germination and colonization. Rain splash is the most common method of dispersal for the spores within a strawberry planting, making proper drainage and canopy management essential.

Management strategies for controlling Colletotrichum acutatum include the use of disease-free planting stock as the first line of defense. Growers should implement rigorous sanitation practices, such as the removal of symptomatic plants, and apply protective fungicide programs throughout the growing season, particularly during the flowering stage to prevent initial fruit infection.

Integrated Pest Management (IPM) is the most effective approach for minimizing losses caused by strawberry anthracnose. This involves monitoring for early signs of infection, maintaining optimal plant spacing to promote airflow, and balancing nitrogen fertilization to avoid excessive vegetative growth that can foster high humidity within the plant canopy.