Sugarcane Ripeners in Florida 1
Chemical ripeners for sugarcane have been studied since the 1920s. Ripeners hasten plant maturity and prolong the period of maximum stalk sucrose concentration. Ripeners typically inhibit apical meristem growth. Presumably, this allows energy ordinarily used for vegetative growth to be diverted to the manufacturing and storing of sucrose.
Since ripeners simply accelerate the natural ripening process, ripeners should not be expected to increase the sucrose content of sugarcane beyond the optimum obtainable through natural ripening (Figure 1). Ripener action is highly variable. The most important factors to consider are the sugarcane variety, climate (temperature and moisture conditions), and timing of ripener application in relation to expected harvest.
Figure 1.
Theoretical ripener effect on sucrose yield.
Ripeners can be incorporated as an important component of sugarcane production management strategy. Natural ripening is induced by low temperatures, water stress, nutrient stress and a shortening of day length. Natural ripening is usually limited during the early portion of the Florida sugarcane harvest season because of plentiful soil moisture, high levels of plant available nitrogen and warm temperatures. Thus, chemical ripening is most effective in sugarcane scheduled for harvest in October and November.
Labeled Ripeners
Currently, Polado L, Roundup WeatherMax, and Touchdown HiTech are the only products registered for use as a sugarcane ripener in Florida. They can only be applied to “last ratoon cane." Use on earlier crops may result in decreased stands in the successive ratoon crops. Roundup WeatherMax at 5 to 12 oz per acre and Polado L at 5 to 14 oz per acre may be applied 3 to 6 weeks prior to harvest. Touchdown Hitech should be applied 3 to 5 weeks prior to harvest at 3 to 11 oz per acre. Total canopy coverage is important. Avoid drift of either product to non-targeted cane or crops. It is critical to avoid newly-planted or freshly-cut cane since inadvertent treatment may result in poor stands.
Expected Results
When applied as directed, the product will enhance ripening and extend the period of high sucrose in responsive varieties. Weather conditions, however, may have a dramatic effect on expressed results. For example, rainfall within 6 hours of application has been shown to reduce effectiveness.
Within 2 to 3 weeks after application, the product may produce slight yellowing to pronounced browning ("burning") of the leaves. Shortening of the upper internodes and spindle death may also occur. As a result of leaf desiccation, an improved trash burn at harvest may be expected.
Most of the enhanced sucrose content will be concentrated in the top of the treated cane stalk. In order to recover maximum sugar at harvest, the stalk should be topped no lower than the base of the fourth leaf.
It is important to follow a harvest schedule adjusted to the variety and amount of ripener applied. Higher ripener application rates require an earlier harvest (e.g., 3 weeks after application) than sugarcane treated with lighter applications.
Footnotes
This document is SS-AGR-215, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First printed October 1991. Revised August 2005. Reviewed October 2008. This publication is also a part of the Florida Sugarcane Handbook, an electronic publication of the Agronomy Department. For more information you may contact the editor of the Sugarcane Handbook, R. A. Gilbert (ragilber@ufl.edu). Please visit the EDIS Web site at http://edis.ifas.ufl.edu.
C. R. Rainbolt, assistant professor, Agronomy Department, Everglades Research and Eduction Center, Belle Glade FL; R. A. Gilbert, assistant professor, Agronomy Department, Everglades Research and Education Center, Belle Glade, FL; A. C. Bennett, assistant professor, Agronomy Department, Everglades Research and Education Center, Belle Glade, FL; J. A. Dusky, professor and assistant dean, and R. S. Lentini, coordinator computer applications, Everglades Research and Education Center, Belle Glade Florida, 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, Interim Dean.
