Novel Seimatosporium Species from Grapevine in Northern California and Their Interactions with Fungal Pathogens Involved in the Trunk-Disease Complex

Seimatosporium spp. and closely related pestalotioid fungi have been larger lesions than those of noninoculated controls. Coinoculations with isolated from vineyards worldwide, but their ecological status in grapevine trunk pathogens (Cryptovalsa ampelina, Diaporthe ambigua, Diatrypella wood is unclear. To determine their involvement in the grapevine trunk- verruciformis, Diplodia seriata, and Eutypa lata), coisolated from the same disease complex, we tested the pathogenicity of Californian isolates wood cankers in the field, brought about increased lesion lengths for S. vitiobtained from vines with general symptoms of Botryosphaeria, Eutypa, fusiforme paired with D. seriata, and S. luteosporum paired with Diaporthe and Phomopsis diebacks. Multilocus phylogenetic analyses revealed three ambigua In contrast, there were no differences in lesion lengths of S. vitis species: Seimatosporium vitis and two newly described and typified spe- and Diatrypella verruciformis or S. vitis and E. lata, inoculated alone or tocies, S. luteosporum sp. nov. and S. vitifusiforme sp. nov. Inoculations to gether. Our findings suggest that Seimatosporium spp. are involved in the woody stems of potted grapevines of both isolates of S. vitis and one isolate grapevine trunk-disease complex, and then- virulence may depend on or afof S. vitifusiforme, but not S. luteosporum, were associated with significantly feet that of trunk pathogens.