Vinclozolin (trade names Ronilan, Curalan, Vorlan, Touche) is a common dicarboximide fungicide used to control diseases, such as blights, rots and molds in vineyards, and on fruits and vegetables such as raspberries, lettuce, kiwi, snap beans, and onions. It is also used on turf on golf courses. Two common fungi that vinclozolin is used to protect crops against are Botrytis cinerea and Sclerotinia sclerotiorum. First registered in 1981, vinclozolin is widely used but its overall application has declined. As a pesticide, vinclozolin is regulated by the United States Environmental Protection Agency (U.S. EPA). In addition to these restrictions within the United States, as of 2006 the use of this pesticide was banned in several countries, including Denmark, Finland, Norway, and Sweden.
Use in the United States Vinclozolin is manufactured by the chemical company BASF and has been registered for use in the United States since 1981. In general, the United States has seen an overall decline in the national use of vinclozolin. In 1992, a total of approximately 135,000 pounds were used. However, in 1997 this number dropped to 122,000 and in 2002 it was down to 55,000 pounds. The following is a compilation of data indicating the national use of vinclozolin per crop (lbs AI/yr) in 1987: apricots, 124; cherries, 3,301; green beans, 13,437; lettuce, 24,779; nectarines, 1,449; onions, 829; peaches, 15,203; plums, 163; raspberries, 3,247; and strawberries, 41,006. In 1997, two applications totaling 285 pounds each, were applied to kiwifruit in California to prevent the gray mold and soft rot caused by Botrytis cinerea.
Preparation and application The following chemical reactions are used to make vinclozolin. One method combines methyl vinyl ketone, sodium cyanide, 3,5-dichloroaniline, and phosgene. This process involves formation of the cyanohydrin, followed by hydrolysis of the nitrile. Vinclozolin is also prepared by the reaction of 3,5-dichlorophenyl isocyanate with an alkyl ester of 2-hydroxy-2-methylbut-3-enoic acid. Ring closure is achieved at elevated temperature. Vinclozolin is then formulated into a dry flowable or extruded granular. It can be applied by through the air (aerial), through irrigation systems (chemigation), or by ground equipment. Vinclozolin is also applied to some plants, such as decorative flowers, as a dip treatment where the plant is dipped into the fungicide solution and then dried. It is also common to spray a vinclozolin solution using thermal foggers in greenhouses.
History of regulations in the US All pesticides sold or distributed in the United States must be registered by U.S. EPA. Pesticides that were first registered before November 1, 1984, were reregistered so that they can be retested using the now more advanced methods. Because vinclozolin was released in 1981, it has gone through both preliminary and a subsequent reregistration. Below is a list of the history of regulations for vinclozolin:
A Data Call-In (DCI), requiring data on product and residue chemistry, toxicity, environmental fate, and ecological effects, have been requested in 1991, 1995 and 1996. Agricultural Data Call-In (AGDCI), to estimate what happens to workers after they apply the fungicide, was issued in 1995. In April 1997, BASF proposed a new use for vinclozolin and thus all risks were reevaluated under the Food Quality Protection Act (FQPA). In June 1998 the EPA put a new safety factor on vinclozolin. BASF voluntarily cancelled vinclozolin use on some fruits and turf. On July 18, 2000 the EPA established that certain meat, bean and dairy products have a 3-year time-limited tolerances for vinclozolin and its metabolites. This led to a phase-out of most domestic food uses for vinclozolin. In September 2000, the EPA received objections to the issued tolerance for beans. Other measures that BASF has taken to reduce risks: cancel use on decorative plants and set up new restrictions on turf which state that the application to turf restricted to golf courses and industrial sites. BASF has proposed to immediately eliminate or phase-out uses such that only use on canola and turf will remain after 2004.
Environmental and health impacts Among the research, a main finding is that vinclozolin has been shown to be an endocrine disruptor with antiandrogenic effects.
Means of exposure The U.S. EPA has examined dietary (food and water), non-dietary, and occupational exposure to vinclozolin or its metabolites. In general, fungicides have been shown to circulate through the water and air, and it possible for them to end up on untreated foods after application. Consumers alone cannot easily reduce their exposure because fungicides are not removed from produce that is washed with tap water. A key example of exposure to vinclozolin is through wine grapes which is considered to account for about 2% of total vinclozolin exposure. It has been determined that people may be exposed to residues of vinclozolin and its metabolites containing the 3,5-dichloroaniline moiety (3,5-DCA) through diet, and thus tolerance limits have been established for each crop. Although vinclozolin is not registered for use by homeowners, it is still possible for people to come into contact with the fungicide and its residues. For example, golfers playing on treated golf courses, and families playing on sod which has been previously treated may be at risk for exposure. Occupationally, workers can be exposed to vinclozolin while doing activities such as loading and mixing.
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