Integrated Crop Management News

Links to these articles are strongly encouraged. Articles may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If articles are used in any other manner, permission from the author is required.

Winter Annual Weeds and SCN – Is There Cause for Concern?

March 25, 2008
Timeline of winter annual weed and soybean growth and SCN activity

By Greg Tylka, Department of Plant Pathology

The frequency of occurrence of winter annual weeds in Iowa fields has increased as more fields are managed with no-till production practices. And in recent years, scientists have discovered that the winter annual weeds purple deadnettle, henbit and field pennycress are moderate to good hosts for the soybean cyst nematode (SCN). Read more about Winter Annual Weeds and SCN – Is There Cause for Concern?

Be Careful with Susceptible Soybean Variety in Rotation to Manage SCN

March 17, 2008
Graph of the number of maturity group SCN-resistant soybean varieties available to Iowa soybean growers, 1991-2007

By Greg Tylka, Department of Plant Pathology


The soybean cyst nematode (SCN) can be managed effectively by growing SCN-resistant soybean varieties. There currently are more that 700 SCN-resistant soybean varieties available in maturity groups 1, 2 and 3 for Iowa growers. Information on the varieties is available in ISU Extension publication Soybean Cyst Nematode-Resistant Soybean Varieties for Iowa (PM 1649, pdf).


Read more about Be Careful with Susceptible Soybean Variety in Rotation to Manage SCN

Pesticide Drift Reduction Starts Now

March 12, 2008

Bob Hartzler, Department of Agronomy

The number of drift complaints in 2007 regarding ground applications of agricultural pesticides received by the Iowa Department of Agriculture and Land Stewardship increased by 36 percent compared to 2006, and was nearly double that of 2004. 

The first step in preventing problems with drift is to develop an effective drift management strategy prior to the spray season.  Important considerations include: Read more about Pesticide Drift Reduction Starts Now

Soybean Rust Overwintering in the South

March 12, 2008
March 5, 2008 Rust Observation Map

By Daren Mueller, Department of Plant Pathology

Despite soybean rust infecting fields in Iowa last fall, the pathogen needs to retrace its steps to get back to Iowa in 2008. The first critical step is for the pathogen to survive somewhere over the winter in places like Florida, Texas or Mexico.

An extensive study on the survival of soybean rust was completed in Florida by  W. Jurick, J. Marios, D. Wright and P. Harmon. Their data was presented at the National Soybean Rust Symposium. Some of the main conclusions were: Read more about Soybean Rust Overwintering in the South

March 2008 La Nina Update

March 11, 2008

By Elwynn Taylor, Department of Agronomy

An area of warm sea surface temperature has formed off the Peru coast. Watch this to possibly “kill” La Nina.  By March 3 the water north of Australia was cooling and west of Peru was warming.Two signs of a La Nina about to fade (and with it the risk of serious Midwest drought diminishes somewhat).  Read more about March 2008 La Nina Update

Try Side-by-Side Trials to Check Fungicide Impact on Corn Yield

March 10, 2008

By Roger Elmore, Department of Agronomy

The decision of whether we should apply a fungicide to corn in mid-season will depend on two sets of factors. First are the main economic drivers: the value of the corn produced, and the costs of the fungicide and its application. The second factor that balances these is the degree to which yield is actually affected.  Read more about Try Side-by-Side Trials to Check Fungicide Impact on Corn Yield

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