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.

Corn Row Spacing Considerations

March 12, 2018
corn row spacing graph.

Corn row spacing and plant population have been the focus of many studies throughout the years in an effort to identify ways to increase yields and minimize production costs. Many studies have shown that there was a yield increase going from a 40-inch row spacing to a 30-inch row spacing. Studies had varying results when it comes to less than a 30-inch row spacing. In some cases, row spacing has had no effect on yield whereas others have seen anywhere from a 2-7% increase in yield by narrowing row spacing from the more common 30-inch.

Consider 15-inch Row Spacing in Soybean

February 22, 2018
graph showing row spacing.

Row spacing is a management decision that often comes up as a priority for achieving high-yielding soybean. Research across the Midwest over several years has consistently shown that soybean planted in narrow rows (<30 inches) has a yield advantage compared to wide rows (≥ 30 inches). The primary reason for this advantage is light utilization; canopy closure is approximately 15 days earlier in 15-inch rows compared to 30-inch rows. Canopy closure earlier in the growing season results in greater light interception and higher growth ra

Frogeye Leaf Spot Fungicide Resistance Confirmed in Iowa Soybean

February 19, 2018
Frogeye leaf spot is a common foliar disease in Iowa, appearing as gray lesions surrounded by a reddish-brown border on soybean leaves.

Plant pathologists at Iowa State University and University of Kentucky have confirmed that isolates of Cercospora sojina, the pathogen that causes frogeye leaf spot of soybean, have shown resistance to quinone outside inhibitor (QoI, strobilurin) fungicides in Iowa.

Should We be Spraying Fungicides on Corn at V12?

February 8, 2018
graph of humidity at ISU research farms

In 2017, we tested several foliar fungicides on corn at six locations in Iowa: ISU Northwest Research and Demonstration Farm (NWRF), Sutherland; Northeast Research and Demonstration Farm (NERF), Nashua; Northern Research and Demonstration Farm (NRF), Kanawha; Southwest Research and Demonstration Farm (SWRF), Lewis; Southeast Research and Demonstration Farm (SERF), Crawfordsville; and the Ag Engineering and Agronomy (AEA) Farm, Boone.

Downwind Buffers and Susceptible Crop Restrictions for New Dicamba Products

January 13, 2018
dicamba spraying diagram

In response to problems with off-target movement and injury associated with dicamba applications on dicamba-resistant (Xtend) soybean, the EPA made significant changes to labels of the new dicamba products.  While much of the discussion has focused on the Restricted Use designation and the requirement for applicators to receive dicamba-specific training, the EPA also clarified how downwind buffers and protections of susceptible crops are to be implemented.

New Dicamba Labels Issued

January 10, 2018

In October 2017, the Environmental Protection Agency reclassified Engenia®, FeXapan™ herbicide Plus VaporGrip® Technology, and Xtendimax® With VaporGrip® Technology as Restricted Use products and added additional restrictions and requirements to their use. One of the additional requirements stated that anyone wishing to apply these products must attend a dicamba or auxin-specific training.

Crop Quality Management for Harvest 2017

December 6, 2017
maximum storage time table

Corn and soybean yields in 2017 were better than expected, which will add to the largest grain surpluses in recent years. As of the November 9, 2017 USDA crop production estimates, national corn yield estimates exceeded 2016 production and were closer to 2016 production in Iowa than preharvest expectations. Soybean yields are estimated to be lower than in the record year of 2016, but total US supply will be larger due to acreage increases.

Over 1,000 SCN-Resistant Soybean Varieties - All but 29 Have PI 88788 Resistance

November 3, 2017
graph showing SCN resistant soybean varieties

Iowa State just released its annually updated list of SCN-resistant soybean varieties online. There are more than 1,000 different named varieties from which to pick. Unfortunately, 973 of the varieties have the same source of resistance genes, on which Iowa SCN populations have built up increased ability to reproduce.

Know Your SCN Numbers

October 28, 2017
sampling area

Now more than ever, farmers need to know if their fields are infested with SCN and at what levels, especially for fields in which soybeans will be grown in 2018. This article explains why and how to determine SCN numbers in fields.