Occurrence, Sporulation and Pathogenicity Studies with Glomerella Cingulata Associated with Crown Rot of Boxed Bananas

SUMMARY

Perithecia and acervuli of Glomerella cingulata occur on all above-ground parts of the banana plant in Honduras but are more abundant on the persistent bracts. Perithecia and acervuli were most abundant in the wet season; few were found during the hot, dry period. Ascospore discharge required moisture or long exposure to 100% relative humidity. Perithecia discharged viable ascospores in diminishing quantities during 6 weeks of periodic wetting and drying. Maximum germination of ascospores occurred in 6 hr at 100% relative humidity at which time 80% of the ascospores had formed appressoria. Mature perithecia were formed on bract tissue 6 days after inoculation, but failed to form at temperatures of 30 C or above although conidia form abundantly at 30 and 32 C. Mycelial growth was retarded at 35 C. The isolates varied in cultural characteristics and pathogenicity to banana crown tissue.