Chaparral™ helps mitigate fescue toxicosis, controls weeds.
Fewer weeds means more forage for grazing. Fewer tall fescue seed heads means less fescue toxicosis. An application of Chaparral™ herbicide early this spring can help accomplish both.
Seedhead suppression can provide the starting point for more effectively managing fescue toxicosis. The seed head is where the alkaloids produced by the endophyte concentrate (at a rate five times higher than in leaves or stems). Reducing or eliminating those seed heads can help decrease the incidence and severity of fescue toxicosis.
“Research across the fescue belt shows that an early spring application of Chaparral controls a wide mix of broadleaf weeds and prevents most tall fescue plants from developing seed heads,” explains Scott Flynn, Dow AgroSciences field scientist. “By suppressing seed heads to prevent their consumption, Chaparral helps mitigate fescue toxicosis in beef cattle grazing operations.”
Toxins in tall fescue peak in the seed head when the seed head is most palatable (generally mid- to late May). The period of highest concentration does not coincide with the visible symptoms of fescue toxicosis because of the toxins’ residual effects. Animals consume high concentrations in the spring and then suffer from heat stress when the effects are exacerbated by high summer temperatures.
Apply Chaparral as early as three weeks prior to seedhead emergence and as late as the early boot stage, with later applications preferred over earlier applications. This keeps the plants in a high-quality vegetative state, while taking infested seed heads out of the grazing picture.
When applications of Chaparral™ herbicide are timed for optimum seedhead suppression, they will control winter annual weeds and other early season broadleaves, such as buttercup; poison hemlock; biennial musk, bull and plumeless thistle; and wild carrot, says Pat Burch, field scientist with Dow AgroSciences. “The residual control Chaparral provides will control several species that emerge after application, including ragweed,” he says.
“Producers will note grass yellowing, which can last at least a couple of weeks,” Burch adds. “However, tall fescue that has been treated with Chaparral for seedhead suppression maintains forage quality longer through the season.”
Because most seedhead production is suppressed, plants won’t produce stems — resulting in a noticeable change in the appearance of tall fescue pastures and a reduction in pasture biomass.
“The good news is, the lost biomass is mostly unpalatable stems and toxin-laden seed heads,” Burch explains. “While the higher-quality forage improves the appetites of grazing cattle, producers likely will need to re-evaluate stocking rates, since cattle increase forage consumption when fescue toxicosis is mitigated.” A rotational grazing program can help boost forage production and utilization.
Any reduction in the carrying capacity of fescue pastures will be short-lived, as fescue will begin growing at a normal rate three to four weeks after application. To minimize the effect this initial slow growth will have on pasture production, fertilize pastures shortly after greenup and apply Chaparral closer to the time of seed head emergence. This will maximize the amount of leaf herbage mass produced before plant growth is slow.
Research trials show that improved per-head gains due to removal of endophyte-infected seed heads more than offset this short-term reduction in carrying capacity. Additionally — depending on weed pressure — the positive forage response to the removal of weedy competition may offset some or all of the effects of this slow growth period.
In University of Kentucky trials on endophyte-infected fescue, cattle grazing pastures where Chaparral was applied to control weeds and suppress seed heads gained 0.58 pound per day more (two-year average) than those grazing untreated pastures. Stockers on fescue treated with Chaparral™ herbicide had an average daily gain of 2 pounds in two years of grazing studies.
“There is no cure for fescue toxicosis,” Flynn notes. “But using Chaparral to suppress seed heads is one of the most effective management tools available. It can be an excellent option where weed control is needed or where a simplified approach to fescue management is desired.”
For more information about using Chaparral to suppress tall fescue seed heads, visit RangeAndPasture.com.
Tips for successful fescue seed head suppression
Label precautions apply to forage treated with Chaparral and to manure from animals that have consumed treated forage within the last three days. Consult the label for full details.
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Chaparral is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.