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.

Using Cereal Rye Cover Crop and Narrow-Row Soybean to Manage Herbicide-Resistant Waterhemp

August 6, 2020
Waterhemp density in soybean with marginal (left) vs. aggressive weed control program plus harvest weed seed control (right) in previous year’s corn.

Waterhemp control is an increasing challenge for soybean producers due to the evolution of multiple herbicide-resistant populations. With dwindling herbicide resources, there is a need to integrate non-chemical strategies into current weed management programs in soybean. Cereal rye is the most common cover crop grown in the Midwest due to its winter hardiness and short life cycle. The high C:N ratio of cereal rye compared to legume or brassica cover crops results in a slow degradation of the residues; thereby, increasing the duration of weed suppression.

Scout Now for Palmer Amaranth

July 28, 2020
meaghan standing next to palmer plant

This is the time of year to begin scouting for Palmer amaranth (Amaranthus palmeri) in Iowa crop fields. While Palmer amaranth has been identified in more than half of Iowa’s counties, new identifications have waned since the widespread introductions in 2016. Palmer amaranth is still a species to watch out for in every Iowa crop field. Minnesota recently reported finding the weed in a county previously not known to have infestations – thus the weed is still on the move.

Unsolicited seed packages in mail

July 28, 2020

Most people are probably aware of the unsolicited mailing of seed packets from China and other countries. The Iowa Department of Agriculture and Land Stewardship (IDALS) has issued guidelines on how to deal with the situation if you should receive one of these packages.  The following statement was made by IDALS.

Why do we care?

Planning a Late Summer Perennial Forage Seeding?

July 23, 2020

Late summer can provide a window of opportunity to seed perennial forage legumes and grasses, whether you want to establish a new forage crop or need to fill in bare and thin spots in an existing forage stand. To help improve the chances for a successful late summer seeding of forages, consider the following.

Field preparation prior to seeding

Scouting reminders for spider mites

July 20, 2020
Twospotted spider mite.

As parts of Iowa enter severe drought on July 14 (D2, US Drought Monitor), I encourage you to scout for twospotted spider mites in crops. Twospotted spider mites can increase whenever temperatures are greater than 85°F, humidity is less than 90 percent, and moisture levels are low. These are ideal conditions for the twospotted spider mite and populations are capable of increasing very rapidly.

Scouting

Potato Leafhoppers Abundant in Soybean and Alfalfa

July 10, 2020
Potato leafhopper adult (top) and nymph (bottom).

This year we have received many inquiries about potato leafhopper (Photo 1) in soybean and alfalfa. Although they are present in Iowa every year, populations are higher than in 2018 and 2019. Usually, potato leafhoppers are only considered a pest of alfalfa in Iowa, but they do feed on soybean, too. Potato leafhoppers prefer smooth leaves and are usually repelled by varieties with pubescence (hairs).

Measuring Conservation and Nutrient Reduction in Iowa Agriculture

July 9, 2020
Agricultural land use over time in Iowa.

An ongoing public concern is the loss of nutrients from agricultural land in the corn belt. In Iowa, nitrogen and phosphorus losses from farm fields are driven by a variety of factors. Since the mid-twentieth century, statewide corn and soybean acres have increased as extended rotations, hay, and pasture declined. Compared to perennial crops and small grain rotations, corn-soybean and continuous corn rotations are leaky systems.

Soybean Gall Midge Larvae Active in Iowa

July 2, 2020
Soybean gall midge distribution from 2018 and 2019 map

Soybean gall midge was confirmed as an economic pest of soybean in 2018. Worldwide, it is only known to occur in five states in the Midwestern US (Figure 1). Research began in 2019 to monitor the emergence of adults and incidence of larval feeding, as well as management options for the pest. This year, soybean gall midge adults were first collected on June 12 and larvae were detected in soybean on June 23.

Planted Non-Bt Corn? Plan to Scout for European Corn Borer

June 12, 2020

Farmers have enjoyed the benefits of Bt corn since its introduction in 1996, particularly “in the bag” transgenic protection from insect pests and the yield loss they inflict. European corn borer (ECB), Ostrinia nubilalis, was particularly challenging and the target of the first Bt hybrids. The adoption of Bt corn in the U.S. prompted a widespread suppression of ECB. Even so, ECB still shows up in conventional cornfields in Iowa and can be a devastating pest.

Pages