Summer Squash Tolerances to Selected Herbicides

Abstract

Abstract Dinoseb (2-sec-butyl-4,6-dinitrophenol), chloramben (3-amino-2,5-dichlorobenzoic acid), ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl) benzenamine], napropamide (2-(α-naphthoxy)-N,N-diethylpropionamide), DCPA (dimethyl tetrachloroterephthalate), and a tank mixture of bensulide [O-O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl) benzenesulfonamide] plus naptalam (N-1-naphthylphthalamic acid) were evaluated for weed control and tolerance of yellow straightneck, crook neck, and zucchini summer squash (Cucurbita pepo L.). Throughout the growing season, napropamide was most injurious to all cultivars. Napropamide resulted in unacceptable injury to young seedlings, and generally reduced early and total yields. DCPA and ethalfluralin treatments were consistently nonphytotoxic. Broadleaf weed control was not acceptable with any treatment due to the lack of control of smallflower galinsoga (Galinsoga parviflora Cav.). Ethalfluralin and napropamide were very effective in controlling annual grasses.