Abscission Agent Registration

CMNP (5-chloro-3-methyl-4-nitro-1H-pyrazole)

The Florida processed citrus industry faces a serious competitive threat from foreign producers, particularly Brazil, based upon the differential in manual harvest labor cost. The Florida industry has addressed this issue by developing mechanical harvesting systems that can bring costs in line with those of Brazilian hand labor. However, widespread adoption and full realization of the efficiencies of mechanical harvesting require an abscission agent (CMNP), a harvesting aid that will selectively loosen mature fruit. The introduction of an abscission agent is the missing component from what is expected to be a new model for citrus harvesting systems. Because of the promising results, steps have been taken in the last few years to move availability of CMNP closer to reality for the Florida grower.

Use of CMNP requires the registration of this chemical as a ‘pesticide’ under the definitions of the U.S. Environmental Protection Agency (EPA). EPA requires specific research protocols be performed to allow an appropriate evaluation of risk to humans and the environment. An Experimental Use Permit (EUP) application was submitted in December of 2009, for use of the agent on 9,000 acres of oranges; EPA’s decision is expected in July of 2011 for the EUP. An application for ˜Full Registration’ was submitted in January of 2011; up to 24 months may be taken to review the application at the EPA before full registration (‘Section 18’) is granted.

In anticipation of a successful review, field use efforts are focused on developing guidelines for use of CMNP with mechanical harvesters for processing oranges. Research is underway to further refine CMNP rates and machine harvester ground speed and shaker head frequency. Additional research is being conducted to determine the impact of environmental conditions on abscission agent efficacy. These current studies, along with those conducted over the last 10 years, will allow development of an interactive grower tool for predicting fruit loosening under various conditions. Such efforts will provide guidance to growers as they make the transition to mechanized harvesting. The availability of abscission chemicals for loosening sweet oranges will promote expansion of acreage that is machine harvested, which will relieve pressures associated with availability and costs of labor for hand harvesting.

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