AnthracnoseAnthracnose is a plant disease common in warm humid areas that infects a variety of plants from trees to grasses. It is caused by a certain fungus Colletotrichum or Gloeosporium. It produces spores in tiny, sunken, saucer-shaped fruiting bodies (acervuli). Symptoms include sunken spots of various colors in leaves, stems, fruits, or flowers. The spots often enlarge, leading to wilting, withering, and dying of tissues. This fungal disease and is promoted by warm temperatures, high moisture, and poor circulation.
Both green and red peppers are affected by this disease. Although the disease does not seriously affect vegetative growth in peppers, it can seriously damage pods and fruits. Symptoms appear on both ripe and unripe pods and are characterized by sunken, circular spots that can grow up to 1inch in diameter. In moist conditions, pink or yellow spore masses may appear.
Sunken lesions that start small and enlarge with time. Salmon colored spore mass observed when fungus is active.
Image Credit: David B. Langston, University of Georgia, Bugwood.org
Spores, with spore measurements, of a species of the fungus Collectotrichum which causes the disease Anthracnose on tomato.
Image Credit: Paul Bachi, University of Kentucky Research and Education Center, Bugwood.org
Vertical section of acervulus showing conidiophores and conidia.
Bruce Watt, University of Maine, Bugwood.org
Basic Facts of Plant DiseasesMany fungi, bacteria, viruses, and nematodes are plant pathogens. A plant pathogen is an organism or agent that incites infectious disease. A distinct sequence of events occurs in the development of a plant disease; these events are known as the disease cycle. The main stages of events comprising the disease cycle include the following:
- production and dissemination of the primary inoculum,
- primary infection,
- growth and development of the pathogen,
- secondary infection,