Graze weeds gone
Leafy spurge has been the bane of ranchers for over a century. Its impact on the farm community is stunning.
Infestations in the Dakotas, Montana, and Wyoming alone are estimated to cost agricultural producers and taxpayers $144 million a year in production losses, control expenses, and other impacts to the economy. North America-wide, it’s estimated that spurge has impacted 2.7 million acres.
Historically, Montana cattle ranchers like John Lesnick’s late father, Leo, could do little to reduce the economic impact of spurge. When the plant’s tissue is damaged, it emits a milky sap that irritates the skin and makes the plant unpalatable to cattle. Once a site reaches the 50% infestation level, cattle refuse to graze at all, rendering the land worthless.
“I remember when I was a teenager, one draw on the ranch was so thick with spurge we couldn’t ride through it without the horse tripping on the stuff,” says John.
At the time, in the early 1960s, it was estimated that over 250 acres of the Lesnick ranch had spurge infestations of 60% or higher. The average density of leafy spurge in these pastures was about 100 stems per square yard.
Today, Lesnick says it’s rare to see a flowering spurge plant on the ranch. So what caused the dramatic decline in a plant that is viewed by many as unstoppable? In a word – sheep.
In 1964, after seeing how a fellow beef producer, Wilbur Holms, used sheep to rehabilitate ground claimed by spurge, Leo Lesnick invested in a small band to graze his infestations. In a little over a decade, the spurge population had dropped, in even the densest stands, to around 5%.
Today the senior Lesnick’s daughter, Peggy, and her husband, Ken Joki, own and operate the Lesnick family ranch. They maintain around 60 ewes in addition to beef cattle. In June, the sheep are grazed on the pastures with a history of spurge. The cattle follow on the same ground in the fall, after competing grasses have reached maturity.
While Joki has no complaints about his present spurge-control regimen, neither does he have illusions about his sheep eradicating the tenacious weed.
“If we stopped grazing, it would come back,” he says. “Its roots are still in the ground just waiting for the chance to kick up adult plants.”
Joki believes that long-term control of spurge for those who don’t graze sheep regularly lies in establishing insects like the black dot spurge flea beetle and the brown legged spurge flea beetle, two introduced bugs that feed on the plant.
Early Large-Scale Success
One of the first of the large-scale beef operations to use sheep to control spurge was the 43,000-acre N-Bar Angus ranch operated by Tom Elliot.
In the 1980s, almost 10% of the central Montana ranch’s acreage was heavily infested with spurge. All efforts to control the infestation with herbicides proved to be temporary fixes, at best.
While the N-Bar battled its spurge infestations, Pete Fay, livestock researcher at Montana State University, was conducting a unique feeding experiment involving sheep and spurge. For years, spurge had been considered toxic to sheep. Unconvinced that it actually harmed livestock, Fay’s sheep-feeding studies proved three things: