The identification, induction of perithecia, and pathogenicity of Gibberella (Fusarium) tricincta n.sp.

Abstract

Fusarium was consistently isolated from leaf spots on English ivy (Hedera helix L.). This Fusarium culture (mass culture) was single spored, and three distinct pigmentation types were evident: brown, red, and white. They appeared to be cultural variants of the mycelial type and were identified as Fusarium tricinctum (Corda) Sacc. Perithecia resulting from pairings of certain combinations of these single-spored cultures, or from the mass culture, were formed on water agar containing cold-sterilized dried stem pieces of coastal Bermuda hay (Cynodon dactylon Pers.). Gibberella tricincta n.sp. is proposed for the binomial of the heterothallic sexual state, which is heretofore undescribed. In vitro inoculation of detached English ivy leaves with ascospores or conidia of the pathogen reproduced the leaf spotting originally observed; however, pathogenicity was very limited under the conditions studied.