Common name: alachlor

U.S. trade name: LASSO

Pre-emergent (PRE) application of alachlor on winter wheat showing twisted/malformed leaves tightly rolled in whorl	Alachlor (PRE) on broadleaf and grass crops and weeds. Note that in the first flat alfalfa and winter wheat have been killed
Alachlor (PRE) on grasses

2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide.

Chloroacetamides (Amides or Acetanilides).


15.

Corn, soybean, grain sorghum, beans.

Most annual grasses; yellow nutsedge; galinsoga, lambsquarters, purslane and black nightshade.

PPI, PRE or early POST in corn; PPI or PRE in soybean; PPI in beans.

Absorbed primarily by emerging plant shoots (grass coleoptile, broadleaf hypocotyl or epicotyl, and secondarily by seedling roots;older plants readily absorb alachlor into roots and translocate upward throughout shoots; translocation in established plants irrelevant as alachlor is phytotoxic only to emerging seedlings.

Not well understood.

May include inhibition of fatty acid and lipid biosynthesis; as well as gibberellin synthesis; does not inhibit seed germination.

Metabolized by tolerant species at the seed germination stage by enzymatic breakdown.

Most susceptible grass and BLW (broadleaf weeds) fail to emerge; susceptible grasses that do emerge appear twisted/malformed with leaves tightly rolled in whorl and unable to unroll normally; leaves do not emerge properly from coleoptile and may do so underground; in BLW seedlings leaves may show some cupping and crinkling and shortened leaf midribs producing a 'drawstring' effect on the leaf tip.

Intermediate (1-4 months); provides season long control (6-10 wks) with no soil residues in the following year to limit rotations.

Oral LD₅₀ = 1100 mg/kg - moderately toxic (LASSO = 2000 mg/kg - moderately toxic).

RESTRICTED use herbicide (DANGER) due to oncogenicity in rats.