RESEARCH ARTICLES/INFORMATION

Research Category: Soybean Disease and Insect Control Year: 2005 Researcher: Allen Xue Institution: AAFC Topic: Occurrence and control of Phomopsis-Diaporthe complex in soybean in Ontario Funding: $10,000 Research Details: The objective of this project is to determine the distribution and predominant species of the Phomopsis-Diaporthe Complex (PDC) pathogens in Ontario. The occurrence and frequency of the PDC pathogens were determined by using 2,700 seeds and 2,700 pieces each of stem and pod from 90 plant samples collected in each year in 2002, 2003, and 2004. Stem infection was common at 78.4% in 2002 and 100% in 2003 and 2004. Pod and seed infection was common at 78.4% in 2002, 32.7 and 1.5% in 2003, and 34.1 and 3.5% in 2004, respectively; in 2002 P. longicolla was the predominant species, representing 63% of the pathogen population. In 2003 and 2004, D. phaseolorum var. caulivora was the common species, representing 44 and 41% of the population. Diaporthe phaseolum var. sojae had the lowest frequency, representing 18, 22, and 22% of the population, in 2002, 2003, and 2004, respectively. Ontario Soybean Growers have funded this research as an effort to understand Phomopsis-Diaporthe complex more extensively so that the information could be used in breeding resistance and developing controls in Ontario. File: