University of Missouri statewide insect trapping network  has indicated flights of both black cutworm and true armyworm in northwest and other parts of Missouri. Moth flights indicate their presence in Northwest Missouri so growers should scout fields.

Corn should be targeted and scouted for black cutworms. These insects are attracted to winter annuals and low-lying areas of corn fields. This pest cuts corn plants off above ground or below ground. You can find these worms at the base of corn plants or below the soil surface curled up into a “C”.  Insects on the soil surface can be controlled, however, feeding below the soil surface may be ineffective with insecticides.

True armyworms are attracted to corn, winter wheat, small grain cover crops and cool season grass pastures. The larvae are not active during the day so scouting should be early morning or late evening. Look at the base of plants and in pastures in the residue at the soil surface. Armyworms pupate when an inch and one-half in length so when worms are this large, there is no need to treat.

Armyworms will congregate and move across the field devouring leaves and leaving only stalks. Wayne Flanary, Field Specialist in Agronomy, said, “I have had many experiences of winter wheat fields destroyed along with cool season grass and hayfields over the years. The insects will devour all the winter wheat leaves and therefore no leaf area to fill grain resulting in a total yield loss. Also, hayfields will have nothing but stems resulting in complete yield loss.”

It is important to keep a close eye on your fields for these two insect pests.

For more information, contact Wayne Flanary, Field Specialist in Agronomy, Buchanan County Extension Center at 816-279-1691.