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,EXTOXNET I'll'-Ii Fi3EPf ION (7)ttp://ace.orst.edu/cgi-6in/mt's/0l/pipsrethephon,iiim
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<br /> EXTOXNET
<br /> Extension Toxicology Network
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<br /> Pesticide Information Profiles
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<br /> A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State
<br /> University, the University of Idaho, and the University of California at Davis and the Institute for
<br /> Environmental Toxicology, Michigan State University. Major support and funding was provided by the
<br /> USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.
<br /> I EXTOXNET primary files maintained and archived at Oregon State University
<br /> Revised 9/95.
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<br /> ETHEPHON
<br /> TRADE OR OTHER NAMES: The active ingredient ethephon is found in a variety of commercial
<br /> herbicides. Trade names for products containing ethephon include Arvest, Bromeflor, Etheverse, r
<br /> Flordimex, Flordimex T-Extra, Cerone, Etherel, Chipco Flores Pro and Prep (223, 316).
<br /> REGULATORY STATUS: Ethephon is a general use pesticide (GUP). Check with specific state '
<br /> regulations for local restrictions that may apply. Products containing ethephon carry the Signal Words
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<br /> "Danger", "Warning", or "Caution" depending on the product (223).
<br /> I CHEMICAL CLASS: organic phosphorus compound /ethylene generator/plant growth regulator
<br /> INTRODUCTION: Ethephon is a plant growth regulator. Its use varies with plant species, chemical
<br /> concentration, and time of application. Ethephon regulates phases of plant growth and development by
<br /> application to various growth sites (1). It is currently registered in the U.S. for use on apples, barley,
<br /> blackberries, bromeliads, cantaloupes, cherries, coffee, cotton, cucumbers, grapes, guava, macadamia
<br /> nuts, ornamentals, peppers, pineapples, rye, squash, sugarcane, tobacco, tomatoes, walnuts, wheat, etc.
<br /> (1, 223, 207). Ethephon's mode of action acts via liberation of ethylene, which is absorbed by the plant
<br /> and interferes in the growth process (1). It is also used in the acceleration of ripening of fruits and
<br /> vegetables (302). Ethephon comes in RTU (ready-to-use), emulsifiable concentrate and aqueous solution
<br /> formulations (223, 316). It may also be used in combination with Terpal (with mepiquat-chloride) and
<br /> Terpal C (chlormequat-chloride) (223).
<br /> TOXICOLOGICAL EFFECTS
<br /> Acute Toxicity: The amount of ethephon that is lethal to one-half(50%) of experimental animals
<br /> fed the material is referred to as its acute oral lethal dose fifty, or L1350. The acute oral toxicity of
<br /> ethephon in rats ranged from 3400 mg/kg (313) to 4229 mg/kg (242, 223, 302). Acute animal
<br /> toxicity studies in a few species show that via the oral and dermal routes, ethephon is relatively
<br /> non-toxic except in hens. An acute study with rats showed an oral LD50 of 1.6 g/kg (EPA toxicity
<br /> category III). An acute dermal study using rabbits showed a dermal LD50 of greater than 5 g/kg
<br /> (EPA toxicity category III) (315). In a rat study, ethephon was administered by gavage for 13 weeks
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