Pendimethalin is a selective herbicide of the dinitroaniline class used preëmergently and postemergently to control annual grasses and certain broadleaf weeds. It inhibits cell division and cell elongation. Technically, pendimethalin is N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitroaniline (CAS 40487-42-1) with molecular weight 281.31 g mol and formula C13H19N3O4; it is a low water solubility, nonvolatile compound that preferentially adsorbs to soil organic matter and shows limited mobility in most soils, with photolysis and microbial degradation governing dissipation and typical field half-lives in soil ranging from several weeks to a few months depending on temperature, moisture and microbial activity; its bioactivity derives from inhibition of microtubule polymerization disrupting mitosis in emerging shoots and root meristems, so label use emphasizes incorporation or soil contact for preëmergent effects and timely application for postemergent control of small seedlings.
Parent: Pendimethalin
Technical grade pendimethalin is supplied with high active ingredient content and low levels of related compounds; typical commercial specifications report active substance content in the range of about 94 to 98 percent by weight for technical material, with total related compounds and unspecified impurities commonly limited to below 5 percent; individual known impurities and related compounds include des-nitro and mono-nitro aniline analogs, minor N-oxidation products, traces of 2,6-dinitroaniline and residual synthetic precursors or alkylated anilines, each of which is typically controlled at levels below 0.5 to 1.0 percent depending on manufacturer and analytical method, and exact impurity profiles should be confirmed by the certificate of analysis for each batch.
Pendimethalin is used as a selective preëmergent and early postemergent herbicide to control a broad spectrum of annual grasses and certain broadleaf weeds in crops, turf and noncrop sites by preventing germination and early seedling development; label recommendations specify application timing, rate, soil incorporation or irrigation and crop rotation constraints to achieve effective weed control while minimizing crop injury.
The chemical formula of pendimethalin is C13H19N3O4.
Pendimethalin 38.7 CS is a formulation containing pendimethalin in a capsule suspension or similar carrier at 38.7 percent active ingredient; its mode of action is the same as the active substance, namely inhibition of microtubule assembly which blocks mitosis and cell elongation in germinating seeds and young shoots and roots, producing a preëmergent barrier and preventing establishment of susceptible weed seedlings.
Pendimethalin is classified as having low to moderate acute mammalian toxicity, but it can cause gastrointestinal irritation, lethargy and other clinical signs if a dog ingests a significant amount; prolonged or high level exposures can produce more serious effects and specific risk varies with dose, product formulation and the animal involved, so contact a veterinarian or poison control center immediately and follow label first aid and medical guidance if ingestion or exposure is suspected.
