Submitted to: Mississippi Academy of Sciences Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2001
Publication Date: N/A
Technical Abstract: The plant pathogens, Colletotrichum acutatum and C. fragariae, cause anthracnose disease in strawberry plants. Colletotrichum acutatum is found worldwide and is increasingly important as the cause of strawberry petiole, stolon, and anthracnose fruit rot. Colletotrichum fragariae is often associated with anthracnose crown rot in strawberry and seems to be restricted to the southeastern U.S. Using light and electron microscopy the ontogeny of the infection process on petioles and stolons by both pathogens on the Chandler strawberry cultivar were observed. Previous studies suggested that C.Fragarie might be hemibiotrophic (obtaining nutrients from living cells before becoming necrotrophic (obtaining its nutrients from host cells it had previously killed) while C. acutatum was necrotrophic throughout its development. Bailey, O'Connell, Pring, and Nash predicted that species of Colletotrichum with a narrow host range, e.g.,C. fragariae,were likely to be hemibiotrophs based on intimacy of host relationship while generalists such as C. acutatum would be necrotrophs. Parbery postulated the trend of biotropic fungi moving towards necrotrophy based on the expansion of food resources. Our exhaustive search of the host tissue infected by either fungus has indicated a very transient biotrophic phase for both C. fragariae and C. acutatum that barely fits phase for both C. fragariae and C. acutatum that barely fits the current concept of hemibiotrophy.