Bio-Control for Leafy Spurge

According to the Sheridan County Weed and Pest, leafy spurge is an invasive forb that was brought to the U.S. from Eurasia through impure seed processing. This weed has taken over Sheridan County, especially targeted in the eastern half.

It reproduces by seed and new shoots from the existing roots of adult plants. It is known for having a high content of milky white sap that can cause irritation to the mouths of cattle. This weed drastically decreases the forage quality of infested rangelands, is unpalatable, and is difficult to control.

SCWPD utilizes multiple methods of control in order to most effectively control leafy spurge and minimize desirable plant damage. One way they control the noxious weed, is using biological control, leafy spurge beetles, which feed exclusively on leafy spurge.

Spurge beetles are the tiny black bugs near top of photo. Grasshoppers and other insects also eat spurge, but many eat beneficial plants as well.

Walker Billings, supervisor of SCWPD, was recently scattering the spurge beetles on a ranch near Clearmont. He talked about how many beetles they were releasing,

The beetles are only a part of controlling the weed. Although a large part of the entire program, other control methods are included. Sheep and goats love spurge, and with controlled grazing on the spurge patch, the plants are stressed, the canopy is eaten down so the plants cannot re-seed. There is also chemical control, and they are finding new and better chemicals to kill the plant or at least stunt it grown for a time.

Walker added that this is a slow spurge year, due to the drought, and it will help to stress the spurge as well, and the beetles can do a better job of killing it.

He said he hopes to establish some colonies of beetles here in Sheridan County, so they can collect the beetles and move them throughout Sheridan and Johnson Counties instead of having them shipped from Montana. He talked about possibly having the community help gathering the beetles.

Although the weed and pest admit that it is doubtful that the spurge will ever be completely eradicated in Sheridan County, spurge beetles are an important part of controlling the noxious plant.