Chemically Speaking - August 2006
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Decisions Issued for Pyrethrins, Piperonyl Butoxide, MGK-264, and Dimethoate
EPA has determined that all but one use of pesticide products containing pyrethrins, piperonyl butoxide (PBO), and MGK-264 are eligible for reregistration, pending the risk mitigation outlined by the Agency. Pyrethrins dust application with a power duster is not eligible for reregistration. First registered in the late 1940s and 1950s, pyrethrins, PBO, and MGK-264 are used to control many types of flying and crawling insects and arthropods. Pyrethrins are often formulated with synergists, such as PBO or MGK-264 to extend the pyrethrins toxic effect.
Mitigation measures outlined by the EPA address residential, occupational, and ecological risks. To mitigate residential risks, the Agency is restricting carpet dust applications to spot treatment only and prohibiting use of products in metered release devices in residential areas (removing day-car centers, nursing homes, schools, and hospitals from product labels). Pyrethrins and PBO use in outdoor misting systems will be restricted by establishing a maximum use rate and precautionary label statements, while MGK-264 will be prohibited from use in these systems.
Occupational risks are mitigated through repackaging and applicator respirator requirements. To address risks to aquatic and terrestrial organisms, mitigation measures include reducing the amount and/or frequency of outdoor sprays and agricultural applications. For pyrethrins and PBO mixtures with agricultural uses, no more than 10 applications will be allowed per season, and minimum retreatment interval will be three days, except under extreme pest pressure, in which case this period is 24 hours.
On July 12, the EPA announced the availability of the interim reregistration eligibility decision for dimethoate. The document describes mitigation measures to reduce the insecticide’s impact on drinking water, workers, and the environment. Maximum application rates will be reduced, as well as the number of treatments per season/year. Minimum retreatment times will be extended. Perhaps most importantly for Florida, use of dimethoate on citrus in this state would be canceled. The PIO is planning to make comments to the docket and all interested parties are urged to call the PIO if concerned. (Pesticide & Toxic Chemical News, 7/17/06, EPA Pesticide Update, 7/31/06).
