Cloransulam-methyl is a novel selective herbicide developed by Dow AgroSciences (USA) in 1997. It belongs to the triazolopyrimidine sulfonamide class of herbicides and is primarily used for post-emergence foliar spraying or soil treatment in soybean fields to control broadleaf weeds.
Mode of Action:
Cloransulam-methyl is classified as a Group B herbicide by the Herbicide Resistance Action Committee (HRAC) (WSSA Group 2) and acts as an acetolactate synthase (ALS) inhibitor. It inhibits the activity of ALS in plants, blocking the biosynthesis pathway of branched-chain amino acids (valine, leucine, and isoleucine), which in turn affects protein synthesis. This ultimately leads to the cessation of cell division, inhibited growth, and death of the weeds. The herbicide is absorbed through the leaves and roots of weeds and accumulates in meristematic tissues (growth points) where it exerts its effect. Its safety in soybeans is attributed to its rapid metabolism into inactive compounds within the soybean plant, with a degradation half-life of less than 5 hours. After application, soybean leaves may exhibit temporary slight chlorosis, but they recover later without affecting yield.
Target Weeds and Application Scope:
(1) Applicable Crops: Spring soybeans.
(2) Controlled Weeds: Various annual broadleaf weeds, including commelina, red smartweed (Oriental smartweed), Pennsylvania smartweed, cocklebur, velvetleaf, common ragweed, three-lobed ragweed, hemp, ivy-leaved morning glory, and sunflower. It also has strong inhibitory effects on sowthistle, perennial sowthistle, and field thistle. Adding an appropriate amount of organosilicone adjuvant or methylated vegetable oil adjuvant during application can improve herbicidal efficacy under drought conditions.
Precautions for Subsequent Crops:
Wheat and barley can be planted 3 months after application.
Corn, sorghum, peanuts, and potatoes can be planted 10 months after application.
Sensitive crops such as sugar beets, sunflowers, tobacco, rapeseed, flax, and cruciferous vegetables can only be planted 22–24 months or more after application.
Main Formulations:
Cloransulam-methyl 84% WG