Submitted to: Mississippi Association of Plant Pathology and Nematology Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 26, 1997
Publication Date: N/A
Technical Abstract: Colletotrichum acutatum is the primary causal agent of strawberry anthracnose fruit rot. Infection of the fruit of the susceptible cultivar Chandler by C. acutatum was studied with light and scanning electron microscopy. Mature unwounded, detached fruits were inoculated by immersion in a conidial suspension (6x106 spores/ml) and then incubated in a dew chamber at 24 deg C, 100% RH, and 16 h photoperiod. The infection process was observed at 4 h intervals for signs of conidial germination and appressorial formation. Conidia germinated readily and formed appressoria 16- 18 hrs after inoculation. The fruit's cuticle layer was penetrated by a thin infection peg formed from the appressorium 21-24 hrs after inoculation. Successful penetration was characterized primarily by the presence of intracellular hyphae, and to a lesser degree, by the presence of a haustorium 24 h after inoculation. Young acervuli appeared by 36 h after inoculation. These observations suggest that C. acutatum follows a subcuticular intramural pathogen infection strategy.