Published online by Cambridge University Press: 12 June 2017
Three herbicide treatments were evaluated for use under clear polyethylene mulch and three types of row covers (spunbonded polyester, double-slitted polyethylene, and perforated polyethylene). Treatments included combinations of bensulide {O,O-bis(1-methylethyl)-S-[2-[(phenylsulfonyl)amino]ethyl]phosphorodithioate} and naptalam {2-[(1-naphthalenylamino)carbonyl]benzoic acid}, and cinmethylin {exo-1-methyl-4-(1-methylethyl)-2-[(2-methylphenyl)methoxy]-7-oxabicyclo [2.2.1] heptane} alone and in combination with naptalam. In 1985 and 1986, all herbicide treatments controlled more than 95% of carpetweed (Mollugo verticillata L. # MOLVE) and large crabgrass [Digitaria sanguinalis (L.) Scop. # DIGSA], except for the combination of bensulide plus naptalam in 1986, which controlled only 73 to 85% of these weeds. In both years, all herbicide treatments reduced crop vigor at 3 weeks but not at 7 weeks after transplanting. Total yield was not different with any of the herbicide treatments in 1985 and 1986. However, in 1986, yields were greater from the bensulide plus naptalam treatment than for the weed-free control. Herbicide treatment did not affect early yields in 1985, but the bensulide plus naptalam treatment was greater than all others in 1986. The use of row covers did not increase herbicide-induced crop injury over that of clear mulch alone. Greenhouse studies indicated that soil-applied cinmethylin reduced muskmelon root and shoot weight. Foliar applications reduced muskmelon shoot weight.