Hard Working Beetles
By Larry Hyslop

A spurge stem borer beetle on leafy spurge

Four ranchers, an Elko County Commissioner, and I are walking across the edge of a meadow. We all walk bent over, as we carefully study the ground for this year’s crop.  This is not a crop of grass or alfalfa, but of beetles, specifically leafy spurge flea beetles. We are the private property of Mike Laughlin and Lee Raine east of Lamoille and Mike is hoping we will find beetles hard at work.

Seven years ago, when Mike and Lee bought this property, it had a bad infestation of leafy spurge. This noxious weed covered the meadows and filled in between sagebrush and bitterbrush, eliminating most forbs and grasses and resulting in poor livestock grazing. Due to leafy spurge’s light green color, the infestation was visible from miles away. This weed is a perennial, so it builds a complex root system and is hard to kill. Dry seed capsules pop, flinging seeds up to 15 feet where they can lie dormant for eight years. Livestock will not eat it since leafy spurge irritates the mouths and intestinal tracts of cattle.

Mike immediately began to rid his property of leafy spurge, spraying the meadow with a herbicide. This worked well but proved to be almost impossible to spray among sagebrush and bitterbrush. Then Mike heard of a bio-control program where apthona beetles are released near leafy spurge.

With the help of the Nevada Department of Agriculture, NRCS, and the Lamoille Conservation District, three types of beetles were released on Mike’s property, near infestations of leafy spurge. The beetles were tiny black and gold-colored flea beetles and a larger variety called a spurge stem borer or “long horn,” named for its large antenna.

Jeff Williams, Elko County Commissioner, asked the ranchers what happens when the beetles run out of leafy spurge, what would they begin to eat then? Research and multiple releases across the country have shown these beetles feed only on leafy spurge. The weeds will probably never be completely eradicated. Beetles and weeds will likely reach equilibrium someday, where a few beetles live off of a few weeds, but keep the weeds from spreading.

We soon found all three types of beetles on leafy spurge leaves. Adult beetles emerge in summer, mate, lay eggs on the soil, and feed on the foliage. Larvae then burrow underground and feed on the roots, especially the main root mass. They go dormant over winter but resume feeding in spring. Mike can tell which spurge plants have been attacked since he can easily pull the stem free from its damaged root mass.

The original beetles were released five years ago, so these are the fifth generation of workers. Mike describes the results as dramatic. Leafy spurge plants still grow among the sagebrush but not nearly as extensive as before the beetles arrived. Even better, grasses and forbs have returned, filling in between sagebrush. The beetles have also spread about a quarter mile from their release sites, killing leafy spurge as they move.  Beetles have even moved onto properties whose landowners do not treat their infestations.

The other three ranchers have also released beetles on their property. They all agree beetles still have much work to do, but the beetles are there, hard at work reducing infestations of leafy spurge.

Elko Daily Free Press, “Nature Notes”, 7/22/2011 © Gray Jay Press, Elko, NV

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