|By KEVIN WALKER
EAST LANSING, Mich. — Chances that soybean rust will reach Michigan this year are relatively low, according to state officials. Furthermore, the odds of a significant soybean aphid outbreak are also low.
Nevertheless, the people at Michigan State University (MSU) are taking no chances, and will monitor the situation in the southern portions of the state.
Farm field plots in 20 counties will be monitored from June through August using scouting techniques. These efforts will take place as far north as Tuscola, Sanilac, Saginaw and Gratiot counties. All counties on the border with Indiana and Ohio will be scouted.
“What we’re hearing up here is that conditions in the South have been relatively dry, keeping inoculum levels low,” said Kurt Thelen, an associate professor at MSU in the department of crop and soil sciences and an extension specialist. “This bodes well for us northerners.”
Approximately 95 percent of the soybean crop in Michigan has been planted.
In addition to scouting for rust, in five of the counties MSU extension educators will also look for evidence of soybean aphids: these include Monroe, Lenawee, St. Joseph, Allegan and Clinton counties.
Soybean aphids were first found in Michigan soybean fields in 2000. When they multiply to large enough numbers they can damage plants and lower crop yields. “So far the forecast for aphid pressure is low,” Thelen said.
As of June 2 no aphids had been found on soybean on the MSU campus, after a sampling of hundreds of small plants. On June 2, 2005 there had already been a 1-5 percent rate of plant infestation at the same locations.
In Michigan there are three trapping locations for aphids: MSU’s Saginaw Valley Bean and Beet Research Farm in Saginaw County, the MSU Entomology Farm in Ingham County and the Kellogg Biological Station in Kalamazoo County.
By the end of June two more trapping locations will be set up: the MSU Extension Office in Monroe County to cover southeast Michigan, and another in Oceana County to cover western Michigan.
Monroe County has a high population of buckthorn, the overwintering host for soybean aphid. This county experienced a heavy, early infestation last year. The location in Oceana County is specifically targeted for vegetable growers in western Michigan, where soybean aphid is implicated in virus spread.
Soybean aphid counts will be posted on a website, www.ncipmc.org/traps, each week. The Michigan traps are part of an eight-state network with 33 traps altogether, with five to six more scheduled to be set up sometime this month.
According to the national soybean rust website (www.sbrusa.net), there are no known reports of rust on commercially planted soybeans in the United States this year so far. Soybean rust was reported earlier this year in Mexico during winter season seed production, before commercial planting of the soybean crop.
Soybean rust has been confirmed in five counties in Alabama, 11 counties in Florida, four in Georgia and one in Texas. Positive tests for soybean rust are done by spore trapping, but a positive test doesn’t mean that plants have actually been infected.
Soybean rust has been found in limited amounts on kudzu in Florida and Alabama during recent observations. The southern states are experiencing hotter and drier than normal conditions, making “viable spore dispersal” less likely.
This farm news was published in the June 14, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.