Root and Foliar Absorption of Atrazine Applied Postemergence to Broadleaf Weeds

Results from both growth chamber and field experiments indicate that root absorption of 2-chloro-4-(ethylamino)-6-(isopropylamino)- s -triazine (atrazine) applied postemergence to small broadleaf weeds is not a requisite for their control. Though broadleaf weeds absorb toxic quantities of atrazine from wet soil, they can be killed by foliar absorption alone because all of their meristems are exposed to a foliar spray. They are particularly sensitive when foliar penetration is enhanced by high relative humidity and wet foliage.