July 22, 2018
Making A Rope Wick Applicator
Control of Johnsongrass (Sorghum Halepense) in Mid-South hay fields and pastures is a constant challenge. In the late summer and early fall, the Johnsongrass grows taller than the other grasses and, if not controlled, will consume the whole field. This perennial’s rhizomes will winter over in the soil producing new growth in the summer, and the airborne seed will start a new infestation in fields that have previously been clean. Johnson grass is palatable forage for cattle, but is too tough and coarse for horses. Johnsongrass can also contain toxic Hydrogen Cyanide under some conditions. Mixed grass and legume hay is good forage for horses, but Johnsongrass should not be part of the mix.
Consistent mowing will help control Johnsongrass in pastures but this cannot be done in hayfields. The herbicide Glyphosate (brand names Roundup and Touchdown) can be effective in controlling Johnsongrass post emergent, but spaying the field will kill the other grasses and legumes as well. One solution to this problem is a rope wick applicator. This simple implement was popular with row crop farmers when Glyphosate was introduced in the 1970’s, but fell out of use with genetically modified crops that can tolerate Roundup and, thus, can be sprayed.
Rope wick applicators are available commercially, but are fairly easy to make yourself. The University of Georgia Agricultural Extension Service has produced a pamphlet, also available on line that has plans and instructions. This plan uses a 3” section of schedule 40 PVC pipe, brass compression fittings, and nylon rope. The brass fittings are a little hard to find in quantity and sometimes leak. Rodgers Sales Co. in Lyon, Ms (662-902-1664) has a kit available that includes PVC fittings with nylon rope. The pipe is purchased locally. The applicator can be made in various lengths and can be mounted either on a front end loader, 3-point hitch or ATV. Cost for a 10 foot applicator should be less than $200 and a 10-foot applicator holds 3 gallons. The concentration of herbicide should be 33%. Wiping should be done in both directions so that the leaves get a thorough soaking, and the height of the applicator should be adjusted above the desirable grasses. Take care not to drive over pastures after wiping a field, as some of the herbicide could adhere to the tractor tires and kill grasses you want to keep. While not perfect, a rope wick applicator can be an effective, economical way to control Johnsongrass.
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