Integrated Crop Management News

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Fill ‘er Up!

August 19, 2008
Graph of 2008 degree day accumulations from May 1

By Rich Pope, Department of Plant Pathology

In a season that started with weather tumult fouling up the planting season in many areas, we have done pretty well in getting the corn and soybean to reproductive stages. Degree days remain behind long-term averages as of August 17.

Goss’s Wilt Prevalent in Western Iowa

August 12, 2008
Image of dark green to black freckles characteristic of Goss's wilt

By Alison Robertson, Department of Plant Pathology and Laura Jesse, Plant and Insect Diagnostic Clinic

This past week several corn samples infected with Goss’s wilt were submitted to the Iowa State University Plant and Insect Diagnostic Clinic. Tamra Jackson at University of Nebraska, Lincoln has also reported an increase in the prevalence of Goss’s wilt in Nebraska this growing season (see Crop Watch, August 8, 2008). 

Plan for 2009 Crop Year by Managing Flooded Soils

August 11, 2008

By Mahdi Al-Kaisi, and Stephen Barnhart, Department of Agronomy
Approximately 1.2 million acres of Iowa farm land affected by flooding early this year have not been planted to any crop. There are potential economic and soil environmental consequences of leaving these soils unattended. The long-term damage to soil and water quality in areas of significant flooding need to be considered when planning for next season’s crop.

Midsummer Scouting for Downy Mildew and other Soybean Diseases

August 8, 2008
Image of downy mildew symptoms

By XB Yang, Department of Plant Pathology and John Kennicker, Iowa State University Extension

Summer soybean disease scouting is revealing some interesting finds due to several years of unusual weather. This is the third year in a row that Iowa has had a cool summer. The summer of 2006 was cool, but not wet; this year and last year, cool and wet.

Soybean Rust and Late Planted Soybeans

August 6, 2008
Map of the US Drought monitor, July 2008

By Daren Mueller, Department of Plant Pathology

Iowa producers are asking if soybean rust will affect the late planted soybean crop. Taking a look at current U.S. locations of soybean rust and understanding the movement of the rust, helps answer the question for Iowa producers.

All Things Considered, It Could Be Worse!

August 5, 2008
Image of base 50 degree F degree days in regions of Iowa from May 1 to August 3, 2008

by Rich Pope, Department of Plant Pathology

Corn and soybean condition has remained remarkably good in general as we enter August. Favorable weather in the early summer certainly has not made up for the early season planting problems that plagued parts of Iowa, but it has allowed crops to recover. The last week of July was warm and allowed vegetative staged crops to make up some lost degree day ground. 

Reviewing Decision Thresholds for Pest Insect Control

July 30, 2008
Image of soybean aphids on a bean leaf

By Jon Tollefson, Matt O’Neal, and Marlin Rice, Department of Entomology

Three tools need to be understood in order to make decisions regarding the control of insects found on crops: damage boundary, economic injury level, and the economic threshold. The existing values for these three variables are now being questioned with the increase value of Iowa’s row crops and the cost of controlling the pests. This article reviews the use of these tools in regards to soybean aphid control.

Watch Soybean Aphid Numbers - NOW

July 30, 2008

By Jon Tollefson, Department of Entomology

Last week the conditions in Minnesota were very good for soybean aphid reproduction. With those conditions, the populations increased rapidly in many locations throughout Minnesota. We have been expecting 2008 soybean aphid populations to be lower as they were in 2004 and 2006, but the 2008 weather has not been exactly “typical.”