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.

Alfalfa Weevils Active Throughout Iowa

May 6, 2020

Adult alfalfa weevils become active and start laying eggs as soon as temperatures exceed 48°F. Like other insects, the development of alfalfa weevil depends on temperature and we can rely on the accumulation of growing degree days (GDD) to predict activity. Alfalfa weevil egg hatching begins when 200-300 degree days have accumulated since January 1.

Take Care When Washing Work Clothes Used Around Pesticides

May 1, 2020
graphic showing different washing instructions

Pesticide applicators and handlers need to wear, at a minimum, the Personal Protective Equipment (PPE) specified on pesticide product labels. Most pesticide labels require a long-sleeved shirt and long pants. Proper laundering of work clothes that may be contaminated with pesticide residues is essential to reduce pesticide handlers’ short- and long-term exposure to pesticides and prevent the potential of residue cross-contamination onto other clothing. 

Mild Winter Favors Bean Leaf Beetle Survival

April 24, 2020
bean leaf beetle on green leaf

Bean leaf beetle adults (Photo 1) are susceptible to cold weather and most die when air temperatures fall below 14°F (-10°C). However, they have adapted to winter by protecting themselves under plant debris and loose soil. Each spring, adult beetles emerge from their overwintering habitat and migrate to available hosts, such as alfalfa, tick trefoil, and various clovers. As the season progresses, bean leaf beetles move to soybean and other hosts. While adult activity can begin before soybean emergence, peak abundance often coincides with early-vegetative soybean.

Survival Effects of Fluctuating Temperatures on Insects

April 22, 2020

The weather this year has been quite variable – several warm days followed by a cold, snowy week in April is just one example of the dramatic changes we’ve experienced in air temperatures (Figure 1). Each winter, we receive the question “Will insect pests be worse/better this year?”, and cold snaps during the spring cause people to wonder “Do fluctuating temperatures affect pest populations?” The short answer to these questions: it depends, but probably not.

Keeping Bees in CRP

April 21, 2020

Over the past two decades, scientists and beekeepers alike observed drastic declines in bee populations. On average, beekeepers lose significantly more honey bee colonies each year and fewer native bee species are spotted in the wild. This is especially apparent in the Midwest where research conducted at Iowa State University observes multiple factors that contribute to the decline in bees and other pollinators. According to an annual Bee Informed Partnership survey, Iowa beekeepers typically lose between 40-60% of their hives each year.

FieldWatch® Launches New Pilot Program in Iowa

April 20, 2020

FieldWatch®, an online system designed to foster communications between growers, beekeepers, and pesticide applicators, is launching a new pilot program in Iowa in 2020 called SeedFieldCheck.

Performance of Preemergence Herbicides on Waterhemp Control in Soybean

April 17, 2020

The battle against waterhemp is complicated mainly because of its extended emergence period (early May until August). Preemergence (PRE) soil residual herbicides serve as a foundation for managing waterhemp, but require follow-up treatments with effective postemergence (POST) products due to late-emerging plants. Group 15 herbicides (HG 15) are commonly used for PRE waterhemp control. However, an increased selection pressure from these herbicides used in corn-soybean rotations has resulted in the evolution of HG 15 resistance in waterhemp populations, recently documented in Illinois.

Seedcorn Maggots Flying in Iowa

April 16, 2020

Seedcorn maggot is a seed and seedling pest of corn and soybean. Plant injury is especially prevalent during cool and wet springs. The larvae, or maggots, feed on germinating corn and soybean seeds or seedlings (Photo 1). Feeding can delay development or kill the plant. Infestations tend to be field-wide instead of in patches like for many other pests. To confirm seedcorn maggot injury, check field areas with stand loss and look for maggots, pupae and damaged seeds (hollowed out seeds or poorly developing seedlings).

Preemergence Herbicide Application Timings: Pros and Cons

April 9, 2020

Preemergence herbicides are the foundation of herbicide-based weed management systems, and effective use of these products is essential to protect crop yields and reduce selection pressure for herbicide resistant weeds. In a perfect world, applying preemergence herbicides immediately after planting would provide the greatest likelihood of maximum performance, but equipment and labor availability limit many farms from using this approach. This article will provide a brief overview of the pros and cons of different application strategies.

Options Available for New Pesticide Applicators

April 8, 2020

The Iowa Department of Agriculture and Land Stewardship (IDALS) is working with the Governor’s office to address pesticide applicator issues that have arisen due to the COVID-19 pandemic. A Proclamation issued April 2, 2020, by Governor Kim Reynolds temporarily suspends some regulatory provisions. IDALS is taking a step-by-step approach to provide regulatory relief.