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Command / clomazone

Chemical Structure

Chemical Name:


Chemical Family:

Isoxazolidinone (none generally accepted).

WSSA Resistance Group:


Crop/non-crop registration:

Soybean, peppers, pumpkins, peas

Sensitive weeds:

Annual grasses and BLW (broadleaf weeds): barnyard grass, Panicum spp., crabgrasses, velvetleaf, common ragweed, lambsquarters.

Application method:


Absorption & Translocation:

Not highly absorbed when foliar applied;readily absorbed by roots and emerging shoots (grass coleoptile and broadleaf hypocotyl) and is translocated to foliage via xylem.

Mode of Action:

Not completely understood; but thought to inhibit the isoprenoid pathway.

Metabolic pathway inhibited:

Inhibition of the isoprenoid pathway stops production of among other things gibberellin, plastoquinone, carotenoids, and the phytol tail of chlorophyll.

Basis of Selectivity:

Metabolized to non-toxic compounds by tolerant species.


Susceptible seedlings typically emerge from treated soil, but are bleached white and become necrotic after a few days.


Intermediate (1- 4 months); decreasing persistence in sandy loam soils compared with silt loam or clay loam soils.


Oral LD50 = 2077 mg/kg - moderately toxic (COMMAND = 2343 mg/kg - moderately toxic).

Additional comments:

Susceptible species in later growth stages may exhibit foliar bleaching when treated POST or when exposed to vapor drifting from nearby treated areas.