Allan McGinty and Darrell Ueckert
Livestock producers and landowners throughout most of Texas and the Southwest are facing a major dilemma dealing with brush infestations in their rangelands and pastures:
- Brush is invading, reproducing, thickening, and growing in grasslands at an alarming rate.
- Costs for many conventional brush management practices have escalated beyond the realm of economic feasibility.
- Few herbicides are available.
- There are more restrictions on herbicide use.
- There is growing concern about pesticides in the environment.
Many factors constrain or prohibit use of conventional brush management methods, including:
- Decreasing ranch size
- Urban encroachment
- Endangered and threatened species
Although a wealth of information on effective brush control technology is available, the current “brush dilemma” can be blamed upon failure among landowners to adopt the available technology or to use the technology in ecologically and economically sound approaches.
Brush Busters is a cooperative venture of the Texas Agricultural Extension Service and the Texas Agricultural Experiment Station to expedite the adoption of effective, individual plant treatment technology by landowners. The program is a “do-it-yourself, user-friendly, environmentally safe, and ecologically sound approach” to rangeland brush control. Brush Busters stresses individual plant treatments to reduce costs, improve control, limit damage to desirable plants, and lengthen treatment life of expensive broadcast treatments. Brush Busters control techniques are simplified for those with little or no previous experience. One of the major brush species targeted by the Brush Busters program is juniper (cedar).
Brush Busters Juniper Control Program
One of the most common errors landowners make is to postpone application of initial and follow-up brush management practices until the brush maturity and/or density necessitates expensive “reclamation” treatments. This is a special concern with juniper. Conventional control methods for mature juniper can cost from $18/acre to over $80/acre (Table 1).
The common-sense, alternative approach is to control juniper before it causes debilitation of desirable forage plants and when the juniper is in the most vulnerable growth stages(s). The facts are:
- Juvenile juniper are easier to kill than mature juniper.
- Capital outlay can be minimized by controlling juniper in the seedling and sapling growth stages and before dense stands develop.
- The array of treatment alternatives can be maximized by controlling brush in the seedling and sapling growth stages.
Tactical brush management systems (TBMS) emphasizes the application of individual plant treatments to juniper seedlings, saplings, or brush regrowth following conventional brush management practices. The efficacy, economics, labor efficiency, and acceptability of individual plant treatments have been greatly improved by several new innovations including all-terrain vehicles (4-wheelers) equipped with sprayers, light-weight backpack sprayers, special nozzles, and highly effective herbicides. TBMS methods are environmentally friendly because control treatments are applied directly to the target plant, thereby reducing or eliminating damage to desirable plants. This high level of selectivity allows landowners to sculpt landscapes to optimize livestock production, as well as wildlife habitat, aesthetic, and real estate values of the land. TBMS methods are more effective than broadcast spraying because of more thorough coverage and the delivery of greater herbicide dosages to the target, yet total herbicide usage is usually much less, than is customary for broadcast applications for woody plant control. Comparative costs for TBMS methods as compared to conventional methods are presented in Table 1.
One of the goals of Brush Busters is to simplify treatment options to expedite adoption by landowners. In 1996, Brush Busters targeted juniper control. Three treatment options were selected. One was a leaf spray using a 1% concentration of Tordon 22K in a water carrier. The second was a soil spot spray using Velpar L at a rate of 2 cc for every 3 feet of plant height or every 3 feet of plant canopy diameter (whichever is greater). The final treatment option was hand grubbing or top removal (for ashe juniper). These three treatment options are explained using a simple three step approach in a leaflet titled “Brush Busters – How to Master Cedar (L-5160).” This publication is available through county Extension Service offices.
Table 1. Comparative costs for conventional and tactical methods for control of juniper.
|Juniper/Acre||Herbicide (lb)/Acre||Cost ($)/Acre|
|Root Plowing||———-||———-||$50 – $75|
|Tree Dozing||———-||———-||$30 – $75|
|Tree Dozing + Fire||———-||———-||$32 – $80|
|Chaining||———-||———-||$18 – $22|
|Chaining + Fire||———-||———-||$21 – $24|
|Individual Foliar Spray||209||0.05||$10.79|
During 1996, in a partnership with DowElanco and Dupont Chemical Companies, large demonstration plots were installed at five highly visible locations, and identified with large, professionally designed signs. The two Brush Busters herbicide treatments were applied at each site. The leaf spray (1% Tordon 22K + 1/4% surfactant + 1/4% HiLite dye) was applied to individual juniper plants using sprayers mounted on 4-wheel ATV’s equipped with three sprayguns. The driver had a spraygun, as well as a man walking on each side of the ATV. These two men had sprayguns connected by 20-foot hoses to the ATV. All sprayguns were tipped with X8 adjustable cone nozzles. Each juniper plant was sprayed to the point of runoff.
The second herbicide treatment was a soil spot spray using Velpar L. The herbicide was applied undiluted to the soil surface midway between the cedar stem and the canopy edge using an exact delivery handgun. The rate applied was 2 ml for every 3 feet of plant height or every 3 feet of plant canopy dia-meter, whichever was greater.
Detailed cost figures were collected for the Brush Busters leaf spray and soil spot spray at the five demonstration locations. For all sites, labor was valued at $5/hour and ATV’s at $2.50/hour. The leaf spray cost per plant varied from 7.4 cents/plant in Taylor county to 18.7 cents/plant in Sutton county (Fig. 1). The Taylor county site was dominated by plants 3 feet high or less, as compared to Sutton county which had plants that approached 6 feet in height, with dense canopies due to heavy goat browsing. The average cost per cedar plant treated for the five locations was 12.9 cents. The Brush Busters soil spot spray was generally less expensive and less variable in cost as compared to the Brush Busters leaf spray (Fig. 2). Soil spot spray cost varied from 5.1 cents/plant in Taylor county to 7.5 cents/plant in Burnet county. Averaged across all five locations, the soil spot spray cost 6.4 cents/plant. Cost per acre for the Brush Busters leaf spray varied from $9.60/acre in Brewster county to over $35/acre in Sutton county (Fig 3). As expected, plant size and density were the controlling factors. Brewster county was characterized by few plants (most less than 3 feet tall), while the Sutton county site was dominated by plants that approached 6 feet in height, with dense foliage stimulated by heavy goat browsing. Cost per acre for the soil spot spray was generally lower as compared to the leaf spray, especially for sites dominated by larger plants. Cost per acre varied from approximately $9.58/acre to $16.90/acre.
One of the advantages of using individual plant treatments is that the quantity of herbicide used can often be reduced as compared to broadcast treatment. Applications of Tordon 22K, the herbicide used in the Brush Busters leaf spray, are limited by label to 0.5 lbs active ingredient/acre (1 quart/acre) or less. Only one site approached this level (Fig. 4). Velpar L applications are limited to 0.66 lbs active ingredient/acre (1/3 gallon/acre). Four of the five sites treated with the soil spot spray received only 0.4 lbs active ingredient/ acre or less of Velpar L. One site (Mills county) was treated with approximately 1.3 lbs active ingredient/acre. This site was dominated by large juniper.
Brush Busters stresses the use of individual plant treatments to:
- Reduce costs.
- Reduce the quantity of herbicide released in the environment.
- Improve the level of control obtained.
- Avoid the need to use expensive broadcast treatments that “paint with a broad brush”.
- Extend the life of broadcast treatments when used.
- Sculpture the landscape to meet specific management goals.
- Remove brush such as juniper before serious damage occurs to the herbaceous understory and soil is lost through erosion.
Early treatment is critical when dealing with juniper, since there are no broadcast herbicide options for control of this plant, and the quantity of herbicide used for leaf spraying individual plants generally doubles with each one foot increase in juniper height. Landowners and managers must identify and put a high priority on those areas that are appropriate for treatment with the Brush Busters methods. They must also use a systems approach when controlling mature juniper with mechanical methods (chaining, grubbing, rootplowing) and incorporate fire, goating and the Brush Busters individual plant treatments to extend the effective life of expensive “reclamation” treatments.
Allan McGinty, Professor and Extension Wildlife Specialist
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