Anthracnose is caused by several different species in the genus Colletotrichum. These fungi cause a fruit rot, crown rot, and/or leaf spots, as well as lesions on petioles and runner stolons. The plants normally don't show symptoms until after being transplanted to the production field. The fungus overwinters as inoculum mainly in infected plants and in plant debris. This inoculum is primarily disseminated by splashing water. To survive, the fungus needs plant tissue, so the inoculum does not remain in the soil for long periods of time as with many other rots.
Symptoms and Disease Cycle
Anthracnose is a problem mainly in rainy, warm harvest seasons. Symptoms of anthracnose fruit rot are light-brown spots on fruit that typically turn dark brown or black and then enlarge. Flowers and flower buds can also become infected and can appear to dry out. Symptoms of anthracnose crown rot are rarely noticed until the plants collapse or die, usually in the fall or spring following transplanting during warm weather. When the crown is cut through lengthwise, a brownish horizontal V shape can be found, originating near the base of a petiole. Leaf spots either resemble ink spots or appear as irregular lesions at the tips or margins of leaves, depending on the species causing the infection. On the runners and petioles, lesions begin as small, red streaks and then turn dark, sunken, and elongated.
Control practices include mulching with straw. When watering strawberries use drip irrigation or carefully hand water. Wet fruit and foliage increases the spread of the disease. The use of raised beds or plastic mulch seems to also increase disease, possibly because of the higher microenvironment temperatures or because water drops bounce and splash off the plastic. Immediately plow down infected areas of a bed, especially if disease occurs in certain areas. This practice may keep infection from spreading.