Submitted to: Strawberry International Symposium Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 10/30/2004
Publication Date: 11/30/2004
Citation: Smith, B.J. 2004. An overview of strawberry anthracnose in north america. Strawberry International Symposium Proceedings, p.28. Interpretive Summary:
Technical Abstract: Colletotrichum species incite serious diseases of many fruit and vegetable crops worldwide, and three species, C. acutatum, C. fragariae and C. gloeosporioides, are major pathogens of strawberry. Strawberry anthracnose crown rot has been a destructive disease in strawberry nurseries and fruit production fields in the southeastern United States since the 1930's. The causal fungus, C. fragariae, may infect all aboveground plant parts; however the disease is most severe when the fungus infects the plant crown causing crown rot, wilt, and death. The presence of the anthracnose fruit rot pathogen, C. acutatum, was first reported on strawberry in the USA in 1990. The fungus had previously been reported causing anthracnose fruit rot of strawberry in Queensland, Australia. The increase in losses due to anthracnose fruit and crown rots in the USA since the 1980's may be related to the shift from matted row culture to the annual plasticulture production system, as well as a change in cultivars being grown. Anthracnose investigations in the USA have concentrated on differences among the three causal Colletotrichum species in their cultural, morphological, and molecular characteristics, their infection processes, and pathogenicity. Studies on the survival of the pathogens in the field determined that survival is dependent on soil temperature and moisture. Studies of the effect of cultural practices on the severity and spread of anthracnose in the field demonstrated that strawberries grown in soils with high nitrogen levels are more susceptible than plants grown in soils with lower nitrogen levels or those amended with calcium nitrate. The use of overhead irrigation and plastic mulch in strawberry fields resulted in more severe anthracnose than when drip irrigation and straw mulch were used. Fungicide efficacy has been determined in in vitro, greenhouse, and field studies; and pathogen resistance to some fungicides has been detected. USDA-ARS and state breeding programs are developing anthracnose resistant cultivars, and several have been released. Methods to rapidly and reliably determine if nursery plants are infected are being developed.