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Publication #SS AGR 262

Recommendations for Spot-Spray Treatment of Tropical Soda Apple with Milestone1

Jason Ferrell and Brent Sellers2

Tropical soda apple (TSA) is a troublesome pasture weed commonly found throughout Florida. For many years, IFAS recommended controlling TSA by either broadcasting or spot-spraying the herbicide Remedy (triclopyr). However, more herbicidal options have recently become available.

In 2005, Milestone (aminopyralid) was registered for TSA control and has since been proven to be highly effective with pre- and post-emergence broadcast applications at 5 to 7 fl oz/acre. Milestone provides more consistent control than Remedy because it acts more thoroughly on the root system. Spot-spray recommendations for Milestone, however, have not been well developed. This document reports the results of a field experiment to determine the rate and application procedure necessary to maximize TSA control with spot-treatments of Milestone.

Since TSA plants tend to be scattered throughout a pasture, under trees or in common milling areas, the easiest way of eradicating TSA plants is often to mix a spot-spray solution based on a certain percentage of the herbicide per volume of water (% v/v). The Milestone label only indicates its usage proportions in terms of amount per 1,000 ft2. To determine the most effective percentage of Milestone per volume of water, spot treatments were performed with Remedy at 0.5% v/v and Milestone at 0.04, 0.11, 0.18 and 0.25% v/v.

Remedy acts very quickly on the plant itself, resulting in complete brown-out or kill within a 2 week period. However, Remedy has no soil action and benefits from 1 or 2 mowing cycles for complete control.

Milestone, in contrast, has soil action and long residual control; it takes 4-6 weeks to kill the entire plant, but has greater movement into the root system (translocation), which results in better control over the long-term. Because Milestone is slow acting and extensively translocated, it is unknown whether complete foliar coverage is essential for optimum control. Therefore, the experiment applied each herbicide to both 50% and 100% of the TSA foliage.

Results

Seven weeks after treatment, Remedy and Milestone (0.11 to 0.25% v/v) applied to the whole plant resulted in greater than 92% control (Figure 1). Milestone at 0.04% v/v sprayed onto the whole plant provided only 60% control. When applied to only half the plant, control ranged from 8 - 76% for both herbicides (Figure 2).

From these data, we recommend Milestone to be applied at no less than 0.11% v/v when spot-spraying TSA plants, and the entire plant should be thoroughly covered with the spray solution. A 0.11% solution would result in 2-1/2 teaspoons (13 ml) of Milestone per 3 gallons of water.

Figure 1. 

Response of TSA to whole-plant applications of Remedy and Milestone 7 weeks after treatment.

Figure 2. 

Response of TSA to half-plant applications of Remedy and Milestone 7 weeks after treatment.

Conclusion

Considering the applicaton rates of Milestone and Remedy, the cost for either product will be similar. Therefore, equivalent control and price can be expected from either herbicide when it is properly applied.

For More Information

EDIS publications:

West Florida Research and Education Center:

Footnotes

1.

This document is SS-AGR-262, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date, April 2007. Visit the EDIS Web site at http://edis.ifas.ufl.edu.

2.

Jason Ferrell, assistant professor, Agronomy Department, Gainesville, FL, and Brent Sellers, assistant professor, Agronomy Department, Range Cattle Research and Education Center--Ona, FL, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer's label.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.