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.

Assessing Corn Rootworm Activity Using Sticky Traps

July 23, 2019
Western corn rootworm.

Western and northern corn rootworm are major corn pests in Iowa and surrounding states (Photos 1 and 2). Farmers have seen several management changes, including the release of four Bt-rootworm traits to suppress corn rootworm larvae since 2003. Although both species are persistent pests, western corn rootworm is particularly adaptable. The Gassmann Lab at Iowa State University (ISU) has confirmed western corn rootworm resistance to all Bt rootworm traits in Iowa.

Potato Leafhopper Management in Alfalfa

July 23, 2019
Hopperburn.

There have been some reports of potato leafhopper activity and plant injury in Iowa alfalfa this season. Some fields experienced winter injury and the cooler spring provided a slow start to plant growth in 2019. It is time to think about assessing alfalfa stands. Potato leafhoppers (Photo 1) do not overwinter in Iowa, but they are persistent alfalfa pests every growing season. Storms along the Gulf of Mexico bring adult potato leafhoppers north and drop them into fields every spring.

Have Our SCN Sorrows Been Drowned?

June 23, 2019

Those looking for any piece of good news in all of the rain-soaked suffering that has occurred in 2019 have asked “Will all this rain and flooding drown SCN”?  Unfortunately, the answer is “no.” The reasons why are explained. And a small bit of good news about the wet growing season and SCN is offered up in this article as well.

Corn Rootworm Egg Hatch Peaking in Southern Iowa

June 18, 2019
Corn rootworm injury.

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. In 2019, the average hatching date will be behind the average, due to cool spring temperatures. Development is driven by soil temperature and measured by growing degree days. Research suggests about 50% of egg hatch occurs between 684-767 accumulated degree days (base 52°F, soil). Most areas in Iowa have reached peak corn rootworm egg hatch (Fig. 1).

Stalk Borers Worth Scouting in Iowa This Summer

June 18, 2019
2019 degree day map for stalk borer.

Within the last week, I have heard about higher-than-normal stalk borer infestations along field margins compared to previous years. According to degree-day tracking of 2019, the caterpillars should be moving from overwintering hosts to corn throughout Iowa this week.

Japanese Beetles Get a Slow Start to 2019

June 17, 2019
2019 degree day map for Japanese beetle.

Several reports from ISU Field Agronomists have indicated Japanese beetles are emerging in southern Iowa. The emergence is about 7-10 days behind the last few years, due to slowly accumulating degree days in 2019. Literature shows Japanese beetle adults need about 1,030 growing degree days (base 50°F) to complete development and will continue emergence until around 2,150 degree days. Based on accumulating degree-day temperatures in 2019, Japanese beetle adults should be active in some areas of southern Iowa this week (Figure 1).

Soybean Gall Midge Confirmed in Iowa and Nebraska

June 15, 2019
Locations of 2019 soybean gall midge traps.

Last year, the widespread outbreak of soybean gall midge took many farmers and entomologists by surprise. There was significant field edge injury and economic loss in at least 65 counties in Iowa, Nebraska, Minnesota, and South Dakota. A small team organized a concerted effort to learn more about the life cycle, biology and management of soybean gall midge in 2019. The first step was to establish emergence cages in various habitat types to better understand where they overwinter.

Submitting Samples to the Plant and Insect Diagnostic Clinic

June 12, 2019

With the crops of Iowa in the ground, it is time to start thinking about seedling diseases. The Plant and Insect Diagnostic Clinic is a resource for corn and soybean growers assessing their field  throughout the season.

Making a diagnosis

The first step in managing a plant problem is to know what is causing the symptoms observed. Accurate pathogen or insect pest identification is one of the most important integrated pest management (IPM) tactics leading to a successful management strategy.

Staying on Top of Weeds in 2019

June 11, 2019

While good progress has been made toward getting crops in the ground, the adverse early spring conditions are likely to complicate weed management throughout the 2019 growing season. The most important step in minimizing problems is to scout fields regularly to identify problems quickly and allow timely adjustments to management.

Pages