Published online by Cambridge University Press: 12 June 2017
Simazine (2-chloro-4,6-bis(ethylamino)-s-triazine), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), and a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) were evaluated for weed control in pecan (Carya illinoensis (Wang.) K. Koch) orchard establishment. Maximum weed control and tree growth occurred in plots treated with diuron and simazine applied at 3.0 and 4.0 lb/A, respectively. During the second year, phytotoxic symptoms were observed in plots which had received superimposed annual treatments of diuron at 3.0 lb/A, but none appeared in simazine or trifluralin plots.