University of California
Herbicide Symptoms

Unknown Mode of Action

HRAC Group: Z

WSSA Group: 17, 27

This category contains miscellaneous products for which the mode of action and family are unknown.  These herbicides are used in field crops, orchards, aquatic settings, vegetation management, and general pest control. For example, dazomet and metam are used as fumigants to kill weeds, diseases, and nematodes.  Endothall is used for aquatic weed control and crop desiccation. Fosamine is used for vegetation management in noncrop areas. Pelargonic acid, clove oil, and vinegar are contact, nonselective, broad-spectrum, foliar-applied products that are used for weed control in organic crop production.

Injury symptoms: These herbicides cause different symptoms. Symptoms are leaf burning, chlorosis, interveinal chlorosis, stunting, swollen stem, leaf distortion, and leaf crinkling.

Chemistry Group and Common Names of Herbicides with Unknown Mode of Action
Used in the United States

Common Name
Pelargonic acid
Cinnamon oil
Clove oil
Corn gluten
Thyme oil
Vinegar (acetic acid)
Webmaster Email: