Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 13, 1999
Publication Date: N/A
Technical Abstract: An extra-cellular protein, Nep1, with phytotoxic activity to dicot plant species was purified from culture filtrates of Fusarium oxysporum. Nep1 caused necrosis when applied to plant cell suspension cultures and leaf tissues. The ability to cause necrosis when applied as a foliar spray illustrates the potential of using Nep1 in herbicidal preparations. Herbicidal activity of Nep1 was demonstrated on many noxious broad leaf weeds including yellow starthistle, spotted knapweed, velvet-leaf, northern jointvetch, dandelion, sowthistle and others. Application rates of Nep1 as low as 1-5 micrograms/ml resulted in extensive necrosis to the plants within 24hr. The effectiveness of Nep1 was minimally influenced by dew period, but strongly affected by the rate of application and spray volume. Penetration of Nep1 into the plant was through natural openings such as stomata and hydathodes. Surfactants such as Silwet 77 and Tween 20 greatly enhanced the activity of Nep1. Additional research is being carried out to examine the activity of Nep1 in other types of herbicidal preparations including biological and chemical herbicides.