Integrated Crop Management News

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Evaluating Herbicide Injury on Soybean

May 25, 2017

The potential for herbicide injury with preemergence herbicides is greater with soybean than corn. The risk increases with environmental conditions that reduce crop vigor and growth rate, and also with heavy rain that moves the herbicide to the depth of the germinating seed or emerging seedling. Much of the state has experienced these conditions, thus it is likely symptoms will be found in many fields as people return to the field with the improved weather.

Preemergence Herbicide Options for Planted Soybean Fields

May 24, 2017

The spread of multiple herbicide resistant weeds brought an end to the era of total postemergence programs in soybean. Unfortunately, a prolonged rainy period prevented applications of preemergence treatments on many planted soybean fields in certain areas of the state. By the time fields are fit for field operations soybeans likely will be emerging and limit herbicide options in those fields.

The Economics of Soil Health

May 23, 2017

The term “economics of soil health” has been used frequently in an attempt to quantify and validate the value of improving soil health. The traditional thinking about assigning dollar values to soil health metrics, which are many, can be very challenging and it is easier said than done.

One of the challenges in putting a dollar value on soil health is that the improvement in health is a long-term process. Expecting an immediate economic return can defeat the purpose of the long-term sustainability of soil health and its cumulative effects on soil productivity.

A Pest of the Past: Have You Seen Hop Vine Borer?

May 15, 2017
hop vine borer

A common caterpillar we include in our ISU field guides is hop vine borer (Figure 1), but I can’t even remember the last time I saw one. I’m wondering if it’s an early-season pest of the past? Archived ICM News articles tell me it was most commonly observed in northeastern Iowa and states to the east. It was considered an occasional pest that caused stand loss in corn, particularly in fields with grassy weeds. Have you seen it lately?

Black Cutworm Monitoring 2017

May 9, 2017
black cutworm feeding on corn leaves and seedling stalk

black cutworm feeding on corn leaves and seedling stalkThis is the time of year when calls about black cutworm (BCW) scouting dates start to roll in, especially when Corn Belt states to the east have reported high moth numbers in traps. Despite what is being observed in states to the east (Illinois, Wisconsin and Indiana), there have been relatively few captures in Iowa.

Update on Palmer Amaranth in Conservation Plantings

May 1, 2017

The 2016 growing season will be remembered by many for the widespread detections of Palmer amaranth across Iowa. While native seed mixes contaminated with Palmer amaranth seed used in Conservation Reserve Program (CRP) fields were the largest source of introduction, it is important to recognize that the weed was also found in at least 7 counties in areas other than CRP fields. Palmer amaranth seed can be transported by machinery, in feed or bedding and by wildlife, thus all fields in Iowa are at risk of being invaded by Palmer amaranth.

Scouting for Pests in Iowa Cover Crops

April 24, 2017
true armyworm

true armywormLandscape diversification, including the use of cover crops, can provide habitat and forage for beneficial insects. This is especially true in the spring when there is a lack of food. Alternatively, cover crops can also support field crop pests, including moths, beetles, flies and slugs. The early spring vegetation, sometimes called a “green bridge,” provides resources until the row crops emerge.

Alfalfa Weevils Active Throughout Southern and Central Iowa

April 10, 2017
alfalfa weevil adult

Adult alfalfa weevils become active and start laying eggs as soon as temperatures exceed 48°F. Alfalfa weevil eggs develop based on temperature, or accumulating degree days, and hatching can start around 200-300 degree days. Start scouting alfalfa fields south of Interstate 80 at 200 degree days and fields north of Interstate 80 at 250 degree days. Based on accumulated temperatures since January, weevils could be active throughout southern and central Iowa (Figure. 1).

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