1 research outputs found
Recommended from our members
Examinations of Fusarium sambucinum on Humulus lupulus and co-infection with hop stunt viroid in commercial hop fields
After an unusually high incidence of Fusarium canker was observed in commercial hop fields of the Pacific Northwest, field surveys were conducted and revealed that canker incidence ranged from 20 to 60% of bines sampled in six commercial fields, as well as wide-spread Hop stunt viroid infection in these six fields. A variety of inoculation techniques and incubation conditions were evaluated in laboratory and greenhouse studies to determine whether Fusarium sambucinum incites girdling symptoms on hop bines, which is characteristic of later stage Fusarium canker infection in commercial hop fields. Koch's postulates were fulfilled, confirming that F. sambucinum incites Fusarium canker and produces girdling, killing the bine. Colonization of detached hop stems with green fluorescent protein-labeled F. sambucinum or F. verticillioides were observed microscopically, but F. sambucinum colonized more aggressively and to a greater extent. Investigation into the effect of relative humidity on colonization of hop stems demonstrated that relative humidities greater than 88% are required for F. sambucinum to colonize green hop stems. Hilling of commercial hop plants was explored as a management strategy to ameliorate canker symptoms or improve yields in commercial fields with wide-spread Hop stunt viroid infection and results indicate that hilling can improve cone yields in commercial hop plantings co-infected with HpSVd and F. sambucinum