The information in this profile may be out-of-date.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.


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Revised 2/96


TRADE OR OTHER NAMES: Trade names for products containing imazethapyr include Contour, Hammer, Overtop, Passport, Pivot, Pursuit, Pursuit Plus, and Resolve (205, 223, 207).

REGULATORY STATUS: Imazethapyr is a general use pesticide with a toxicity classification of III (slightly toxic). Check with specific state regulations for local restrictions which may apply. Products containing imazethapyr must bear the signal word "Caution" on their label (223). It is currently being tested on alfalfa, clover and other crops in the U.S. and is being sold on these commodities outside the U.S. (207).

CHEMICAL CLASS: imidazole compound

INTRODUCTION: Imazethapyr is an imidazole compound used as a selective herbicide. It is applied preplant incorporated, preemergence, at cracking, and postemergence. The compound controls weeds by reducing the levels of three branched-chain aliphatic amino acids, isoleucine, leucine and valine, through the inhibition of aceto-hydroxyacid synthase, an enzyme common to the biosynthetic pathway for these amino acids. This inhibition causes a disruption in protein synthesis which, in turn, leads to an interference in DNA synthesis and cell growth. The compound is used to control grasses and broadleaved weeds including barnyardgrass, crabgrass, cocklebur, panicums, pigweeds, nightshade, mustard, smartweed, velvetleaf, jimsonweed, foxtails, seedling johnsongrass, lambsquarters, morningglory and others. Tolerant crops include soybeans, peanuts, dry and edible beans, peas, alfalfa and imidazolinone resistant/tolerant corn. Additional research is being conducted on other leguminous crops (205, 223, 207). Imazethapyr comes in aqueous concentrate formulations. It is also formulated and may be combined with other herbicides (223, 207).





Physical Properties:

Exposure Guidelines:


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References for the information in this PIP can be found in Reference List Number 10

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.