Texas Mountain Laurel Control Using Basal and Foliar Individual

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					         Texas Mountain Laurel Control
             Using Basal and Foliar
           Individual Plant Treatments
             Robert K. Lyons, Extension Range Specialist
              G.T. Dickerson, CEA, Edwards County
                                                                                April and May, 1995.            Both
                                                   Summary                      treatments used a mixture of 25%
                                                                                Remedy, 10% Cide-Kick II, and 65%
                                      ♦    Low-volume and streamline basal      diesel. One treatment used the
                                      treatments were applied in 1995 and       streamline basal method of herbicide
                                      low-volume and foliar treatments          application and the second treatment
                                      were applied in 1996.                     used the low-volume basal method.
                                      ♦ The low-volume basal method             All plants were multi-stemmed, which
                                      was superior to the streamline.           made basal treatment difficult on the
                                      ♦ Foliar treatment is the least           larger plants.
                                      expensive approach, but plant-kill              Three treatments were estab-
                                      cannot be evaluated until 1997.           lished at the same location south of
                                                                                Rocksprings in August, 1996. The
                                                 Introduction                   1995 low-volume basal treatment


B     OTTOM LINE                                                                using 25% Remedy, 10% Cide-Kick
                                            Texas mountain laurel is com-       II, and 65% diesel was applied in one
               Low-volume basal                                                 plot. In a second plot, a low-volume
                                      mon to the Hill Country, is a potential
treatment of plants to 5 feet in                                                treatment using 25% Remedy and
                                      poisonous plant problem for live-
height produced 72% apparent                                                    75% diesel was applied. A third plot
                                      stock, and has a potential to increase
plant-kill and 87% for plants under                                             was treated with a foliar spray of
                                      in areas cleared for wildlife habitat
3 feet.                                                                         0.5% Remedy, 0.5% Reclaim, 0.25%
                                      improvement.        Previous control
                                      measures appear to have been              emulsifier, and 0.5% HiLite dye in a
                                      unsuccessful.                             1:4 diesel:water emulsion.
                                            Basal treatments appear to have
                                      potential for control of many Texas                     Results
                                      woody plant problems. However,
                                      multi-stem plants are often hard to       1995 Trial
                                      treat using basal methods. Foliar               This demonstration was evalu-
                                      treatments are generally easier to        ated for plant control level in July,
                                      apply than basal treatments but are       1996. Following treatment in 1995,
                                      sometimes not suitable because of 1)      all plants in both treatments showed
                                      loss of leaves or 2) leaves with heavy    90-100% defoliation. Results from
                                      wax coatings that make herbicide          the 1996 evaluation are shown in
                                      absorption difficult. This demonstra-     Table 1. Considering all plants in the
                                      tion was established to determine the     treatments, the streamline basal
                                      effectiveness of basal and foliar         method provided 41% plant-kill
                                      treatments for control of Texas           compared to 72% for the low-volume
                                      mountain laurel.                          method. Considering plants under 3
                                                                                feet in height, there were no
                                                 Experiment                     differences for the streamline method.
                                                                                However, 87% of plants under 3 feet
                                           Two treatment plots were estab-      in height showed no sign of life in the
                                      lished south of Rocksprings, Texas in     low-volume plot. Plants varied in
size up to 5 feet tall. Treatment cost
for the chemicals was about $0.23/
plant.
                                          Table 1. Apparent plant-kill 14 months after treatment for basal treatments
1996 Trial                                applied in 1995.
     Because this demonstration was
only established in August, 1996,                     Treatment and Plant Size                     Percent Plant-Kill
results are preliminary. Defoliation      Streamline basal - all plants                                    41
was observed in all treatments in the
fall of 1996. This defoliation is         Streamline basal - under 3 ft tall                               41
encouraging with the foliar treatment
because it shows that the herbicide       Low-volume basal - all plants                                    72
mix penetrated the waxy leaf of the       Low-volume basal - under 3 ft tall                               87
mountain laurel which must occur to
have a chance of controlling the plant.
Of course, defoliation does not mean
plants have been killed. Plots will be
evaluated for plant control level in
1997. One point that can be evaluated     Table 2. Treatment, number of plants treated, spray volume, and treatment cost for
currently is treatment cost (Table 2).    Texas mountain laurel plants in the 1996 demonstrations.
Cost for the foliar spray was $0.09/
plant compared to $0.18 to $0.34/                                                         Spray volume/           Cost/
                                                     Treatment              Number
plant for the low-volume treatments.                                                        plant, oz.           plant, $
The difference in cost between the two
low- volume treatments is due to the       Low-volume w/o
                                                                              125                1                 .18
volume of spray used (Table 2), not        Cide-Kick
from a difference in spray cost.
     Mountain laurel is reported to be     Low-volume w/ Cide-Kick             73               1.75              0.34
a plant that may recover after
apparently being killed. Therefore,        Foliar                              55                7                0.09
observation of the 1995 low-volume
treatment will continue to establish
long-term effectiveness of this method.

Conclusions and Implications

♦     The low-volume method ap-
pears to be superior to the streamline
method for control of Texas mountain
laurel.
♦ Concentrating control efforts on
small plants appears to provide a
higher level of control and should
reduce treatment costs.
♦ If the foliar method is success-
ful, it will be the method of choice
because of cost and ease of
application.