Problem pests target Kansas farm crops

TOPEKA ( KSNT ) – Experts with Kansas State University say some nuisance insects are causing big problems for farmers in the Sunflower State.

K-State’s Research and Extension Office said in a recent report there are three problem insects munching on some of the state’s cash crops as the weather turns warmer. These pests pose a danger to rural farmers in as they can cause extensive damage to their plants if proper countermeasures aren’t taken.

K-State Entomologist Jeff Whitworth says farmers are facing a combination of both dry conditions and alfalfa weevils in north-central Kansas. Alfalfa stems in April are usually seven to eight inches in length but, after a recent survey, are only four to five inches.

“The fields that were treated (with insecticide) two weeks ago seem to be holding pretty well,” Whitworth said. “One of the things we’ve urged producers to do this year is to make sure they cover the foliage adequately. That’s really important because the insecticides labeled for alfalfa weevils are contact insecticides, which means weevils need to come into contact with the insecticide to control them.”

The current recommendation for dealing with these pests is to apply 10-15 gallons of insecticide per acre. If temperatures remain in the 40-70 degree Fahrenheit range, the alfalfa weevils will continue to feed regularly.

Whitworth says the weevils will feed for seven to 10 days before they enter the next stage of their life cycle, forming pupal cases on the ground or in tree canopies that look like small cotton balls. Consistent temperatures at or above 80-85 degrees Fahrenheit will force the adult weevils to leave the fields before returning in the fall to mate and lay eggs.

Another problem pest farmers should keep an eye out for is pea aphids. These target pea, clover, alfalfa and broad bean crops.

“They’re sucking the juice out of the plant, so if they’re competing with those plants for moisture, you may have to consider a pea aphid treatment,” Whitworth said. “However, it takes 50 or more (aphids) per stem before I would even consider a treatment.”

Whitworth also warns farmers to be prepared for army cutworms in wheat fields. These insects develop into miller moths around the end of May before they migrate to higher elevations.

“These moths may aggregate in large numbers, and thus be a serious nuisance prior to migrating out of the state in late May,” Whitworth said.

To check your fields for the presence of army cutworms, dig around the soil near the base of your plants in several places throughout the field. Be sure to look for plants that appear stressed. Army cutworms appear as small larvae with a dusty coloration that feed above ground. If you see an abundance of turkeys, skunks or other birds in your fields, you may likely have an army cutworm infestation.

To find more information on pest control in Kansas crop fields, click here .

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