Integrated Crop Management News

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Keep Monitors, Sensors and Scales Accurate During Harvest

September 29, 2022
Corn moisture's influence on yield monitor error.

When heading to the field for harvest, it’s important to make sure your monitors, sensors and scales are getting accurate numbers. Taking the time to calibrate your combine yield monitor is the first step in making sure you are using high quality yield data to make decisions in your operation.

Sap Beetles in Corn: Are they Pests?

September 23, 2022
Sap beetle.

Sap beetles are a relatively common insect in cornfields, typically seen each year around harvest. People usually notice sap beetles (and other ear-feeding pests) while doing pre-harvest yield checks. Adult sap beetles are usually less than ¼ inch long and oval. Most are dark colored and sometimes have orange or yellow spots (Photo 1). Sap beetles can be distinguished from other beetles in corn by their antennae, which have a knob at the end. Larvae may also be found on corn ears. The larvae are small and white with a light brown head, and they turn yellowish as they mature.

Corn Rootworm egg Hatch Behind Schedule this Year

June 21, 2022
Accumulated soil degree days in Iowa.

Corn rootworm egg hatch in Iowa typically occurs from late May to the middle of June, with an average peak hatching date of June 6 in central Iowa. Even with recent warm temperatures, hatching is a bit delayed this year due to cool spring temperatures. Development is driven by soil temperature and measured by growing degree days (GDDs). Research suggests about 50% of egg hatch occurs between 684-767 accumulated GDDs (since January 1; base 52°F, soil).

Japanese Beetle Adult Emergence Begins in Southern Iowa

June 21, 2022
Growing degree days map.

The cool spring has delayed development of many important crop pests across Iowa. However, with recent warm temperatures, Japanese beetle adult emergence has been on track with previous years. Japanese beetle adults begin emergence when approximately 1,030 growing degree days (GDD; base 50°F) have accumulated since January 1 and will continue emerging until 2,150 GDD have accumulated. Japanese beetle adults likely began emerging in the southern portion of the state last week, and emergence will likely occur within the next two weeks in northern Iowa (Figure 1).

Soybean Gall Midge Adult Emergence Begins

June 17, 2022
Soybean gall midge adults.

This week, the first soybean gall midge adults (Photo 1) were collected in Iowa near Wall Lake in Sac County (Monday) and near Sutherland in O’Brien County (Thursday). This is similar to when soybean gall midge emergence was first detected in Iowa in 2021. The first Midwest report of soybean gall midge emergence in 2022 was on June 7 near Davey, Nebraska. You can keep up with soybean gall midge emergence at

Go on the Offensive Against Soybean Cyst Nematode

June 16, 2022
Digging soybean roots in late June to check for SCN.

The best way to manage the soybean cyst nematode (SCN) is to grow SCN-resistant soybean varieties in rotation with the nonhost crop corn. Almost all soybean varieties planted by farmers in Iowa in 2022 contain SCN resistance genes from the breeding line PI 88788. Unfortunately, PI 88788 resistance has lost much or most of its effectiveness.

Start Scouting for Stalk Borers in Southern Iowa

June 10, 2022

Stalk borer is an occasional pest of corn, but it can be persistent in some fields, especially those fields near fence rows, terraces, and waterways that serve as overwintering sites. Tracking degree days is a useful way to estimate when common stalk borer larvae begin moving into cornfields from their overwintering hosts. Foliar insecticide applications are only effective when larvae are migrating and exposed to the insecticide. Start scouting corn for larvae when 1,300-1,400 degree days (base 41°F) have accumulated.

Using the Late Spring Soil Nitrate Test in 2022

June 7, 2022
Nitrogen management chart.

This year, corn planting was delayed due to an unseasonably cold spring, and at this time corn growth stage ranges mostly from the V2 to V6 across the state. Many producers had doubts concerning preplant nitrogen (N) application due to high N fertilizer prices, and now some are wondering about possible in-season diagnostic tools to assess a potential need for supplemental in-season N application.

Scout for True Armyworms this Spring

June 7, 2022
True armyworm feeding on soybean leaves.

True armyworm is a migratory pest from the southern U.S. Each spring, volunteers help us monitor for true armyworm moths during April and May and weekly updates are posted on the ICM Blog. Although a trapping threshold does not exist to indicate whether a certain area might be at high risk for true armyworm feeding, we can use information from the trapping network to guide scouting efforts.