Weed wiping, developed in New Zealand in the 1970s, means you only apply herbicide to the weeds standing above the grass. This is better for the environment as well as your pocket because the herbicide will hit the target and little will be wasted. The risk of drift is reduced because the herbicide is soaked into a rotating blanket, carpet or brush and then wiped onto the weeds, making it more suitable for use close to water features.
Most weed-wiping equipment works in a similar way. The herbicide is pumped to the covered roller or brush rotor, which rotates in the opposite direction to travel. Being height adjustable, the roller can be set to allow for a coating of herbicide to be wiped on the underside of leaves, where there is often less waxy covering and the chemical can be absorbed more easily.
You should take a look at the Wessex Rotowiper from Broadwood International. This model's rot-proof and UV-stabilised carpet has interwoven loops punched through to the rotor that hold moisture drops for longer. A neoprene rubber strip prevents spray drift and aids foaming. Two check valves keep the carpet evenly coated with chemical.
Another weed-wiping system you might consider is the CTF Contact 2000 from ATV equipment specialist Logic. Again designed for towing behind a quad bike and powered by the quad's electrics, this unit features a contra-rotating brush to liberally coat each weed plant with herbicide.
You should also look at the weed-wiping systems from Quad-X. The most basic of these is the Weed Destroyer - equipped with an absorbent, contra-rotating roller and towed either in-line or offset. Height adjustment is in seven set positions.
The 2.16m wide Xterminator, also from Quad-X, has dual rollers. The first lifts the weeds and the second separates out any clumps to give a more even chemical application.
Additionally, Quad-X supplies the Wipeout. This model features a weed detection unit that automatically applies chemical to the rollers when required.
All systems from Quad-X use a process of atomisation where chemical is applied in the form of micro-bubbles that attach themselves to the rollers without burst.
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Sally Drury has been reporting on product developments and testing kit for 29 years. The advice given in this helpline is independent.