Integrated Crop Management News

Iowa State University researchers recently published their annual fungicide trial data for soybeans in 2019, revealing a continued decline in efficiency among the quinone outside inhibitors (QoI) class of fungicides in preventing foliar diseases in soybeans.

Iowa State University researchers, with funding from soybean checkoff through the United Soybean Board and Iowa Soybean Association, have confirmed that over 70 isolates of the pathogen Cercospora sojina (cause of frogeye leafspot in soybeans in Iowa) are resistant to quinone outside inhibitor (QoI) fungicides.

This article summarizes our 2019 corn foliar fungicide trials that were done 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 Farm (AEA) near Boone.

The 2019 growing season was challenging for farmers in many parts of the state, especially because cold and wet soil conditions in April significantly delayed planting. Thistle caterpillar was the most abundant insect statewide, though multiple species of caterpillars, Japanese beetle, soybean aphid, and soybean gall midge were observed in soybean.

Choosing corn hybrids and soybean varieties is one of the most important crop management decisions to be made. It is a hard decision to make because it is typically made months before the growing season begins. This article will explore where to find yield trial information, how to interpret yield trials, and what to consider in selecting cultivars.

Continuous corn is a "three strikes and you’re out" situation. And the first strike is automatic – high residue volume. This is how a farmer recently described it to me.

Resistant varieties continue to be a key tool for managing the soybean cyst nematode (SCN).  With financial support from the soybean checkoff through the Iowa Soybean Association, Iowa State University annually compiles a list of SCN-resistant soybean varieties that are available for use in Iowa. 

The updated list of maturity group 0, I, II and III varieties is now available for free online in the Iowa State University Extension Store.

Crop residue serves an important role in physically protecting soil from erosion during rain events or high winds, as well as enhancing the soil biological activity by providing sources of organic carbon and nitrogen for its energy needs.

Fall nitrogen (N) fertilizer application continues to be popular for several reasons, including lower cost, time for application, equipment availability, often better soil conditions, and competing springtime field activities.

This year continues the chain of growing seasons with extremes and rapid changes beyond our long-term experiences. This made for periods of both stress and favorable crop growth despite the planting dates. Frost, potentially killing in the northern half of Iowa, is expected between October 11-13.

Very variable weather this season will result in variable corn and soybean yield within and between fields. Entire fields or portions of fields were planted later than usual or were not planted. This will result in variable removal of phosphorus (P) and potassium (K) with harvest. Reduced yields combined with continued low market values create uncertainty about P and K fertilization decisions for the 2020 season.

Taking time to verify combine adjustments made in the shop match with the field conditions may seem time consuming but can minimize harvest loss as well as profit loss. This article discusses how to evaluate for pre-harvest loss and losses during harvest, and the types of in-field adjustments that can be made to minimize harvest losses.

Fall is one of the best times for managing perennial and biennial weeds found in pastures or other areas maintained in perennial grass. As perennials prepare for the upcoming winter they move energy reserves from shoots to their perennial vegetative reproductive structures (e.g. rhizomes, perennial rootstocks).

Corn earworm  (Photo 1) is common in Iowa corn. It is a migratory pest, migrating from the southern and southeastern U.S. every summer. There are two general fights to the Midwest every summer, but the first flight is not of economic concern. Iowa’s corn is more vulnerable to infestation of the second flight, arriving in late July. Yield losses can occur in late-planted cornfields, where caterpillars can infest >50% of plants.

Harvest is quickly approaching and most are anticipating a highly variable corn and soybean crop. Below are some reminders for regular maintenance, adjustments, and final checks to make sure your combine is ready to hit the fields soon.  

With delayed planting across the state in 2019, it is important to monitor crop development to determine unique grain drying needs this fall.

With delayed planting across the state, it is important to plan ahead for potential harvest challenges. Scout your fields for crop development to determine whether you might have potential problems with immature, frost-damaged grain, and wet grain.

While there is significant uncertainty about this year’s harvest weather, the struggles with previous year soil compaction may still be lurking in corn and soybean fields across Iowa. This article will highlight challenges with wet conditions at harvest and opportunities to minimize the long-term consequences of harvesting fields with wet soils.