Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/9/1997
Publication Date: N/A
Technical Abstract: Hemp sesbania [Sesbania exaltata (Raf.) Rydb. ex A. W. Hill] is a problematic weed in row crops throughout much of the lower Mississippi River alluvial plain. An isolate of the fungus Colletotrichum truncatum (Schw.) Andrus & Moore (NRRL # 18434) has shown potential as bioherbicide for controlling this weed. In greenhouse experiments, spores of C. truncatum formulated with unrefined corn oil, various surfactants, and other adjuvants reduced free moisture requirements, spray rates, and inoculum densities. In field trials conducted in soybeans in 1996, weed control ranged from 75-95%. Soybean yields were significantly greater in plots treated with the bioherbicide in an unrefined corn oil/Silwet L-77 surfactant formulation and in a newly-developed flowable powder formulation containing unrefined corn oil, an experimental oil-wax-surfactant mixture, water-absorbant starch, and a silica granulating agent as compared to other bioherbicide, oil, and surfactant formulations. These results indicate that bioherbicide performance in non-irrigated cropping systems can be improved through innovative formulation approaches.