Colonization and inoculum production of Gibberella zeae in components of wheat residue

Cereal crop residues represent the most important inoculum source for the development of Fusarium head blight in wheat and barley. There is little information on the level of colonization or the contribution of different parts of the wheat residue to inoculum. In this study, wheat residue tissues including nodes, floral bracts (glumes, lemmas, and paleae), and kernels were evaluated for Gibberella zeae colonization and inoculum production. Gibberella zeae was recovered from all residue tissues. Colonization, determined as the percentage of each residue fraction colonized by G. zeae, was greater on nodes than on kernels and floral bracts. Ascospores were produced by G. zeae on all residue tissues studied. Tissues differed in the quantity of ascospores produced with kernels supporting the development of more ascospores per gram of tissue than nodes and floral bracts. Information from this study may assist in the understanding of colonization and ascospores production of G. zeae in different residue tissues.