Rapid evaluation of Fusarium spp. as a potential biocontrol agent for weeds

An accurate method is described for evaluating the relative effectiveness of isolates of Fusarium avenaceum as potential biological control agents for weeds such as spotted knapweed and wild oat. The method uses seeds that have been disinfected, placed in tubes containing water agar, and challenged with various isolates of F. avenaceum. Evaluatory data on the pathogenicity of the fungi are obtained after 14 d, when plants and fungi both are grown on water agar in the lab. Commonly, potential biocontrol agents are tested on seeds placed in the soil, but up to 60 d may be required for results. However, comparative studies using the soil test vs, the water agar test indicated that the water agar tests are giving comparable results to those from greenhouse tests but in a shorter time (14 vs. 60 d). Also, both water agar and soil tests were done with a number of crop plants including wheat, barley, alfalfa, and wild oat with comparable results. Thus, this method has the potential to screen many pathogens that may have potential biocontrol activities in a shore time.