Colletotrichum karstii

Colletotrichum karstii is a significant fungal pathogen within the Colletotrichum gloeosporioides complex. It is primarily known for causing anthracnose, a destructive disease that impacts a wide array of agricultural, horticultural, and ornamental plant species globally. This pathogen is notorious for its ability to cause both field symptoms and post-harvest rot in fruit and vegetable commodities.

The host range of Colletotrichum karstii is exceptionally broad, spanning from temperate fruits like strawberries and apples to tropical crops such as mangoes and citrus. It can infect various plant tissues, including leaves, stems, flowers, and mature fruits. Its versatility allows it to remain present in agricultural environments throughout different growing seasons.

Typical symptoms of infection include the development of circular or irregular lesions that are often sunken. These lesions frequently turn dark brown or black as the tissue necroses. Under humid conditions, the pathogen produces slimy masses of conidia, which are often pinkish or orange, serving as a primary source of secondary inoculum that spreads throughout the crop canopy.

Environmental conditions play a critical role in the epidemiology of this disease. Colletotrichum karstii thrives in warm, humid climates, where splashing rain and high humidity facilitate the dispersal of spores from plant to plant. The pathogen can survive in soil, on crop debris, or as latent infections on host tissues, making it difficult to eradicate completely once established.

Effective management requires an integrated pest management (IPM) strategy.

• Removal and destruction of infected plant material to reduce inoculum levels.
• Improvement of air circulation within crop rows and greenhouses.
• Application of fungicides during high-risk periods, focusing on rotation to prevent resistance.
• Selection of disease-resistant varieties and use of pathogen-free planting material.
• Implementation of strict sanitation protocols for tools and machinery used in the field.