Left unchecked, weeds, insect pests and diseases can damage or destroy crops and reduce yields significantly, becoming a multimillion dollar problem for North Dakota producers.

To help producers fight back, six trained scouts regularly monitor fields throughout the state during the growing season to detect insect pests and diseases; determine where they’re concentrated and the damage they’ve caused; and alert producers and other stakeholders.

These scouts, who work out of North Dakota State University’s Research Extension Centers, are a key component of the NDSU Extension Service’s Integrated Pest Management (IPM) program. The data the scouts collect help determine whether pest economic thresholds have been or likely will be reached. An economic threshold is when a pest population or disease has reached a high enough level for producers to take action to prevent economic losses.

Extension shares this information through the weekly Crop and Pest Report (online at https://www.ag.ndsu.edu/cpr) and by email. Producers also learn about the latest pest issues at meetings and other educational events such as Research Extension Center field days, and through Extension specialists’ and agents’ news releases, columns and radio programs, and consultation.

The data also is used in forecasting models that help producers determine the risk of a particular pest or disease and when to take control measures. Forecasting models are available for issues including wheat midge, small-grain diseases, potato late blight and sclerotinia in canola.

Providing producers, gardeners and homeowners with strategies for controlling pests, diseases and weeds is another major part of IPM. These strategies are aimed at keeping a pest, disease or weed out of an area; showing producers how to monitor their fields, identify pests and determine economic thresholds; protecting the environment and beneficial insects or pathogens; and reducing the risk of pests, diseases and weeds developing resistance to pesticides and herbicides.

“The idea is to understand the pest’s biology and exploit that information using different management tools so we are not entirely reliant on pesticides,” says Patrick Beauzay, a research specialist in NDSU’s Plant Pathology Department and the state IPM program coordinator.

Once a pest population becomes resistant to a pesticide, the pesticide can’t be used on that pest again, he notes. Plus, developing new pesticides can take more than 20 years, and few, if any, pesticides have been developed recently, so the available chemicals need to be useable as long as possible, NDSU Extension entomologist Janet Knodel says.

Here are some strategies NDSU IPM experts recommend as alternatives to chemicals:

• Cultural - Use crop rotation to break pests’ life cycle; choose planting dates to minimize the risk of certain pests; plant pest-free seed; adjust the harvest date to minimize damage; and plant in field margins a trap crop that’s a preferred host of a problematic pest to concentrate the pest, such as wheat stem sawfly, in a small area.
• Host plant resistance - Select crop varieties that are resistant to pests and diseases, such as Glenn hard red spring wheat for Fusarium head scab resistance.
• Mechanical - Use cultivation or hand weeding (for gardens) to reduce weeds; install screens or physical barriers to keep weeds out of home gardens or landscaping; and use tillage practices to bury or expose pests or pest-infested residue.
• Physical - Store seed in a cool, dry place to prevent mold and insect pest development.
• Biological - Introduce parasitoids, predators or natural disease agents.

“Determining the best IPM strategies includes using the right ones for the current pest problems,” Knodel says.

Producers help develop strategies. When Jared Hagert, who farms near Emerado, found he had a soybean aphid problem year after year, he began hosting NDSU research trials on his farm.

“I feel it’s important to provide some access to real-world growing conditions for research,” he says.

County Extension agents also play a huge role in IPM, often serving as the first line of defense for producers and homeowners.

Julianne Racine, agricultural and natural resources agent for LaMoure County, had just learned about weed and pest management for row crops last year when a producer asked her to help determine if his aphid population had reached the economic threshold level.

“That lesson could not have been timelier,” she says. “Upon arrival, there was more than one producer waiting. We walked through the field as I explained what I had just learned.”

When Finley homeowner Dennis Lindstrom brought a nest made of mud into Extension’s Steele County office in Finley, agriculture and natural resources agent Angie Johnson worked with Knodel to identify it as a mud dauber (a kind of wasp) nest.

“The word ‘wasp’ directly places fear in the homeowner’s eyes,” she says. “However, the mud dauber wasp is a beneficial insect as it is not your typical stinging wasp. With correct identification, we were able to prevent the homeowner from applying an insecticide to the wasp nest.”

Lindstrom, who has a large garden, is glad he has a place to go with insect and weed questions.

“It’s handy,” he says. “If Angie doesn’t know what the bug or weed is, she can find out.”

Identifying insects is very important because only 10 to 15 percent are pests, Knodel says. The majority are beneficial; they eat other insects, break down organic matter in the soil or are an important food source for other wildlife, such as birds.

Identification of weed pests is just as important, says Tom Peters, sugar beet agronomist for NDSU and University of Minnesota Extension.

Waterhemp, for example, is a fast-spreading weed that produces 150,000 to 250,000 seeds per plant and can reduce crop yields. However, it may be confused with other weeds in the pigweed family.

Visit https://www.ag.ndsu.edu/ndipm for more information about NDSU Extension’s IPM program.

NDSU Agriculture Communication - July 15, 2016