RESEARCH ARTICLES/INFORMATION

Research Category: Soybean Disease and Insect Control Year: 2005 Researcher: Tom Welacky Institution: AAFC Topic: Enhance and characterize soybean cyst nematode (SCN) resistance and develop management controls (IPM) to reduce SCN populations and associated diseases Funding: $130,000 Research Details: This project was funded by the CORD program and by OOPSC. The addition of genetic sources for resistance to SCN in varieties has been increasing over the past several years. Agronomic performance evaluations over the past year indicate that SCN resistant varieties are equal to or better than non resistant SCN varieties. SCN resistant varieties increased by 22% as compared to the past few testing years. The next important change in reducing SCN field populations will be the introduction of other sources of resistance besides PI 88788 resistance. Information on each variety reaction has been collected by monitoring for the number of SCN that reproduce on their roots in the field. This information has been compiled for the past 5 years for two locations. Our race/Hg survey to date is finding that approximately 10% of the field SCN populations can reproduce on PI 88788. This low level of reproduction on PI 88788 is encouraging for Ontario growers since several of the north central states down to Tennessee are indicating preliminary results of reproduction on PI 88788 of 27-100% in most of their fields ex: Illinois – 100%, Indiana – 27%, Tennessee – 100%. Field population counts from the survey indicate that about 60% of the 325 fields have SCN populations of 500-2,000 eggs/100g of soil. Populations of this medium level have potential to explode in numbers if growers do not maintain close control with best SCN management practices. It is also an indication that (60%-plus) growers have reduced their populations from the mid-nineties to controllable levels. Timing of alternative resistance sources is critical at this stage of SCN management in Ontario fields as well as the maintenance of non host crop rotations. SCN convey root diseases such as Sudden Death Syndrome fusarium root rot. Our results verified that SDS incidence was dramatically higher in areas with high SCN populations. SDS is beginning to spread in Ontario and it is closely associated with SCN especially with higher populations. Thus reducing SCN will help to reduce the incidence of SDS. Investigation of possible non host crops or soil amendments that would reduce SCN has continued. Field and greenhouse tests are showing hybrid developed millet to be a good non host crop. Soybean hull pellets were tested on a preliminary small scale in the greenhouse and there was a non significant trend in SCN reduction as the rates of pellet material increased but the results were very variable. File: