Published online by Cambridge University Press: 12 June 2017
Five preplant, soil-incorporated herbicides were evaluated over a 2-year period for their effect upon the growth of representative varieties of 15 common species of spring-planted annual flowers. Of these, α,α,α,-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) was effective in combining freedom from plant injury with control of weeds. Only in phlox (Phlox nana compacta Nutt., var. Fireball) was growth reduced significantly over the 2-year period by this herbicide at 2 lb/A while petunia (Petunia hybrida, var. Snow Lady) was reduced in 1 of 2 years. N,N-dimethyl-2,2-diphenylacetamide (diphenamid) at 4 and 8 lb/A was effective and ethyl N,N-dipropylthiocarbamate (EPTC) at 4 lb/A was fairly effective, but both were tolerated by fewer flower species. N-(2-mercaptoethyl) benzenesulfonamide S-(O,O-diisopropyl phosphorodithioate) (bensulide) at 10 lb/A and methyl 3,4-dichlorocarbanilate (swep) at 5 lb/A were not phytotoxic to any species but were relatively ineffective in controlling the weeds present.