New Forage Pest

New Forage Pests Are Showing Up in Parts of Missouri

Sugarcane aphid infestations can hit fast. (Photo by Tim Schnakenberg, University of Missouri)

Agronomists in parts of Missouri started noticing significant populations of sugarcane aphids in the state 2016. At that time, the aphids were in late-season Sudan grass and forage sorghum stands. This was just the latest in a trend of new pests affecting forage and hay protection across parts of the country.

Tim Schnakenberg, field specialist in agronomy with University of Missouri Extension, notes while infestation can be spotty, when a new pest comes into an area, it happens quickly. "Agricultural insect pests seem to develop when we least expect them," he says.

Along with the sugarcane aphid, yellow aphids are also causing forage producers concern. They have the ability to damage pastures and reduce hay yields. Yellow aphids tend to gather in masses on stems and leaves to feed, causing leaves to yellow or redden.

"Traditional insecticides do not offer effective control," Schnakenberg stresses. "So far, Transform WG and Sivanto 200SL are the only products that seem to work, though others may soon follow. Generally, these are legal for grain sorghum. However, always consult the label for special labeling in your state and if it can be used in a forage situation."

A practical way to deal with aphids, he adds, is to convert acreage to a millet variety aphids don't affect.


Another new insect in Schnakenberg's area is the bermudagrass stem maggot. This was found in Barry County last year, but forage specialists believe it may have been in the southwestern part of the state prior to this. Bermudagrass growers in Gulf states have seen the pest for several years.

Like sugarcane aphid, the stem maggot affects mid- to late-season growth and can cause yields to taper off quickly. First signs of an infestation are usually when upper terminal leaves look frost-damaged and die. Inside the stem, a small white maggot can usually be found.

Schnakenberg says the standard control recommendation for this maggot is to spray an insecticide seven to 10 days after the previous hay harvest or grazing. In this case, he says "inexpensive pyrethroid insecticides can be effective ... if applied timely."


Missouri Extension entomologist, Kevin Rice, adds two more emerging pests to the list of those he says producers need to monitor for. Both can damage alfalfa. These are the brown marmorated stink bug and the spotted lanternfly.

The brown marmorated stink bug feeds on alfalfa and can be found in at least seven Missouri counties to date. The spotted lanterfly affects vineyard and walnut trees so far, but could potentially infest alfalfa, corn and soybeans.