Designing a Screening Method for Organic Seed Treatments

Abstract

Certified organic crop producers have limited options available for controlling seed related diseases. I have developed a screen that could be utilized to test various plant extracts as a possible seed treatment. In the initial screen, I tested paper birch (Betula papyrifer) and staghorn sumac (Rhus typhina) extracts against 4 plant pathogens: Fusarium solani, Phytophthora sojae, Rhizoctonia solani, and Pythium spp. The highest concentration of the sumac extract (25.0 micrograms/ml) reduced the growth of R. solani by 67%, F. solani and Pythium spp. by 100%, and P. sojae by 80%. The highest concentration of the sumac extract (25.0 micrograms/ml) reduced the growth of F. solani and Pythium spp. equal to or greater than the commercial seed treatment fungicides. The highest concentration of the paper birch extract (25.0 micrograms/ml) reduced the growth of R. solani by 47%, Pythium spp. by 40%, and P. sojae by 40%. Neither the sumac or the paper birch extract reduced the germination of soybean seeds.