Anthracnose

Anthracnose is a group of plant diseases caused by fungi, primarily Colletotrichum species and related taxa. These pathogens affect a wide range of hosts, including fruit crops, vegetables, ornamentals, and trees, in tropical and temperate regions. The diseases are characterized by necrotic, often sunken lesions on leaves, stems, flowers, and fruits, and can lead to significant yield losses and quality degradation.

Symptoms and signs vary by host but typically include water-soaked or pale lesions that enlarge into irregular brown to black necrotic areas. On leaves, lesions may coalesce and cause blighting or premature leaf drop; on fruits, lesions become sunken, leathery, and may crack; on stems, cankers may form and girdle the tissue. Moist conditions favor the development of fruiting bodies and spore production, with acervuli containing conidia visible within lesions.

Disease cycle and epidemiology: Infected plant debris acts as a primary inoculum source. Spores are disseminated by rain splash and wind-driven moisture, with infection usually requiring surface moisture and susceptible tissue. Warm temperatures and high humidity facilitate infection and disease development. Many Colletotrichum species can persist in soil and on plant debris between crops, enabling recurring outbreaks.

Management: Control relies on integrated strategies. Sanitation to remove infected debris, crop rotation, and destruction of volunteer hosts reduce inoculum. Use of resistant or tolerant cultivars where available, proper spacing and pruning to improve air flow, and irrigation practices that minimize leaf wetness help reduce infection risk. When necessary, preventive or early curative fungicides may be applied, with rotation among chemical groups to delay resistance. Early detection and tailored management based on the crop and pathogen species are important for effective control.