The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.


Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised 9/95.


TRADE AND OTHER NAMES: Trade names for products containing demeton-s-methyl include Meta-Systox I, Meta-isosystox, Azotox, Bay-18436, Bay-25/154, DSM, Duratox, Metasystox 55, Mifatox, and Persyst (1,2).

REGULATORY STATUS: Demeton-s-methyl is no longer registered for use in the United States (11).

INTRODUCTION: Demeton-s-methyl is a systemic and contact insecticide and acaricide that is a member of the organophosphate family of chemicals. It is absorbed and translocated within the plant in sufficient concentrations to kill insects that feed on the plant by sucking its juices. It is used to control aphids, sawflies, and spider mites in fruits, vegetables, potatoes, cereals, ornamentals, and in forestry. Demeton-s-methyl replaces methyl demeton, a mixture of demeton-s-methyl and demeton-o-methyl sold as Meta-Systox. Demeton-s-methyl is more toxic to insects than demeton-o-methyl (1, 7). Classified as Category I - highly toxic, products containing demeton-s-methyl bear the SIGNAL WORD: DANGER (3). It is available as an emulsifiable concentrate (1).




PHYSICAL PROPERTIES AND GUIDELINES: Demeton-s-methyl is incompatible with alkaline materials (10). It is hydrolyzed rapidly in alkaline media and more slowly in acidic and neutral aqueous media (2). It is non-corrosive (10). When heated to decomposition, demeton-s-methyl emits very toxic fumes(9).

Physical Properties:

Exposure Guidelines:


Bayer AG/ Miles
P.O. Box 4913
Kansas City, MO 64120


References for the information in this PIP can be found in Reference List Number 5

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product label/ing or other regulatory requirements. Please refer to the pesticide product label/ing.