Soybean Disease Update

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Soybean Cyst Nematode
Do not ignore soybean cyst nematode. Soil sampling after harvest before any fall tillage is recommended for fields to be planted next season to soybeans following this year’s crop. Do not plant SCN susceptible varieties without soil testing first. Soil sample bags are available from the county Extension offices for $10/sample bag.

Soybean Cyst Nematode Survey
As soybean harvest begins we will be contacting growers to see if they want to participate in this needed survey to assess SCN numbers in fields. The last survey was in the mid-90s. If you have a field with a history of soybean production and want to have the field included please contact me at 302-831-4865 or contact your county agent.

Soybean Rust Update
On September 16, soybean rust was reported in Coffee, Crisp and Irwin counties, Georgia; Coffee and Tipton counties, Tennessee; Barbour, Chambers, Cherokee, DeKalb and Henry counties, Alabama; and Warren County, Kentucky. On September 15, soybean rust was reported in Yell County; Arkansas; Laurens County, Georgia; and Lauderdale, Leake, Newton, and Winston counties in Mississippi. On September 14, soybean rust was reported in Craighead, Jackson, and Lawrence counties, Arkansas; Calhoun County, Florida; St. James and St. Tammany parishes, Louisiana. As the soybean crop matures, more soybean rust reports are expected north of the current distribution.

Rust continues to increase along the Mississippi most of these new detections are on soybeans that will not likely be impacted by rust this late in the season. Sampling continues in Delaware and will until October. The risk of rust is low for us unless some hurricane or tropical storm develops that brings spores north. The latest wet weather systems have been southerly so no transport in our direction. Except for a few coastal counties, the Carolinas have been dry, which has limited spore production that could come our way. Keep abreast of the situation by checking the national ipmPIPE website at www.sbrusa.net.

sbrmap17Sep09