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:
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 | |
| Conventional Methods | |||
| Root Plowing | ---------- | ---------- | $50 - $75 |
| Tree Dozing | ---------- | ---------- | $30 - $75 |
| Tree Dozing + Fire | ---------- | ---------- | $32 - $80 |
| Chaining | ---------- | ---------- | $18 - $22 |
| Chaining + Fire | ---------- | ---------- | $21 - $24 |
| Tactical Methods | |||
| Individual Foliar Spray | 209 | 0.05 | $10.79 |
| Hand Grubbing | 434 | ---------- | $6.18 |
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 variedfrom
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.
Summary
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.
