Metribuzin in the yard and garden

What is metribuzin?

The IUPAC name is 4-amino-6-methyl-4H-1,2,4-triazin-5-one 3-tert-butyl.

Also known as: 4-amino-6-methyl-4H-1,2,4-triazin-5-one 3-tert-butyl, Lexone, Sencor, Metribuzine.

IUPAC name

4-amino-6-methyl-4H-1,2,4-triazin-5-one 3-tert-butyl

CAS number

21087-64-9

Molecular formula

C8H14N4OS

Molecular weight

214.28 g/mol

SMILES

CC(C)(C)C1=NN=C(N(C1=O)N)SC

PubChem CID

30479

Regulatory consensus

2 regulatory and scientific bodies have classified Metribuzin. The classifications differ — that's the data.

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where your yard encounter metribuzin

• agricultural herbicide (potatoes, soybeans)
• crop residues
• groundwater

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Metribuzin:

• S-metolachlor + metribuzin reduced-rate program
  Trade-offs: Reduced (not eliminated) metribuzin use. Better groundwater profile than full-rate.
  Relative cost: Similar
• Cover crop suppression + mechanical cultivation
  Trade-offs: Labor-intensive. Less consistent than chemical control. Requires timing expertise.
  Relative cost: Variable; potential savings on herbicide

Frequently asked questions