Wipers Whip Pasture Weeds
Weed wipers can be an effective and economical weed control tool for graziers, says Jim Johnson, a soil fertility and crop specialist with the Noble Foundation.
"If you can graze desirable forages so that weeds are 6" taller than the forages, a weed wiper will work for you," he says.
Wiper or wick applicators are sometimes used to control volunteer corn in soybean fields. A herbicide is supplied to an absorbent surface that, when passed over the field, wipes the chemical on weeds taller than the crop.
In one version, a pipe with small holes in the bottom is covered with an absorbent canvas. The pipe, filled with herbicide solution, is mounted on a vehicle so it rides above the crop but will contact the weeds. The covering wicks the herbicide out of the pipe through the small holes and applies chemical to weeds as the unit passes over them.
In the most basic unit, the pipe is used as the reservoir for the herbicide. A throttling valve is used to regulate the amount and rate of air inside the pipe.
Other models connect the pipe to a tank with a pump that’s turned on and off as needed to prime the wiper. Better models have a hooded sprayer mounted above the wiping surface to wet it as needed.
Rather than canvas, some wick applicators use braided cotton rope plumped into a pipe. Rope sections are 8" long and overlap.
"Many times it’s necessary to wipe weeds from opposite directions to get thorough coverage," says Johnson. "But better models with hooded booms use a counter-rotating drum, which improves coverage and eliminates the need."
Some units are mounted on the front of ATVs. Others are pulled behind like carts with wheels on the ends. Mounting an applicator on a front-end loader makes it easy to adjust height on the go, Johnson adds.
With a wiper applicator, Roundup (glyphosate) can be used to control almost any weed in any crop as long as the weeds are taller than the crop, he says.
"With a properly adjusted wiper, herbicide is only applied to the weeds. This reduces the amount of herbicide used and introduced into the environment and reduces or eliminates damage to non-target species."
Wipers eliminate spray drift, too. And herbicides with 2,4-D, pichloram, dicamba or triclopyr can also be used to increase control of tougher perennials like horse nettle, briars and tree sprouts.
"You can purchase wipers or wicks fully assembled, as kits you put together or build one completely from scratch," says Johnson. "They can be small hand-held units or as large as 45’."