Pyroxasulfone (KIH-485) is an experimental herbicide developed by Kumiai Chemical Industry Company (White Plains, NY) that has potential for weed management in corn, soybean, cereals, and cotton (Anonymous, 2006). The herbicide has been reported to have activity on a broad spectrum of weeds, including Digitaria species, Panicum species, Setaria species, barnyard grass (Echinochloa crus-galli), velvetleaf (Abutilon theophrasti), Amaranthus species, common ragweed (Ambrosia artemisiifolia), common lambsquarters (Chenopodium album), jimsonweed (Datura stramonium), and Polygonum species (Anonymous, 2006).
Sweet corn is an important vegetable crop in Ontario, valued at nearly $23 million (Mailvaganam, 2006). Currently, there are only three registered soil-applied herbicides for annual grass control: dimethenamid, EPTC and S-metolachlor (Ontario Ministry of Agriculture, Food, and Rural Affairs, 2006). The registration of pyroxasulfone would provide Ontario sweet corn producers with a new, broad-spectrum herbicide that controls selected annual grass and broadleaf weed species. Furthermore, if used in a diversified, integrated weed management program, it would reduce the selection intensity for herbicide-resistant weeds. Although the mode of action of pyroxasulfone is not completely understood, it is thought to be a seedling growth inhibitor that interferes with fatty acid biosynthesis. The spectrum of weeds controlled with pyroxasulfone is similar to the acetanilide herbicides such as S-metolachlor, acetochlor, and alachlor. However, pyroxasulfone provides superior control of certain important broadleaf weeds such as common ragweed and velvetleaf when compared with other acetanilide herbicides (Dyer et al., 2004; Geier and Stahlman, 2004). Pyroxasulfone may also provide superior control of some annual grasses such as wild proso millet (Panicum miliaceum), fall panicum (Panicum dichotomiflorum), and crabgrass (Digitaria spp.) (Anonymous, 2006). Pyroxasulfone has a relatively long soil half-life at 35 to 45 d (Anonymous, 2006).
Sensitivity of sweet corn to herbicides is dependent on the application rate, hybrid, and environmental conditions. Sweet corn hybrid sensitivity has been documented for foramsulfuron (Diebold et al., 2003), bentazon (Diebold et al., 2004), prosulfuron (O'Sullivan and Sikkema, 2001), mesotrione (O'Sullivan et al., 2002), nicosulfuron (Corbett et al., 2005; O'Sullivan et al., 2000; Robinson et al., 1993; Stall and Bewick, 1992), primisulfuron (O'Sullivan and Sikkema, 2002), isoxaflutole (O'Sullivan et al., 2001), and thifensulfuron-methyl (Soltani et al., 2005b). Before pyroxasulfone can be registered for use in sweet corn, hybrid sensitivity must be determined.
There is no published information on the sensitivity of sweet corn hybrids to the preemergence (PRE) application of pyroxasulfone. Therefore, the objective of this study was to determine the sensitivity of Harvest Gold, GH2041, GH9589, GSS9299, GG214, GG446, GG763, and GG447 to pyroxasulfone applied PRE.
Corbett, C.L., Soltani, N., Hamill, A.S., Sikkema, P.H., Bowley, S. & Robinson, D.E. 2005 Tolerance of three sweet corn hybrids to a postemergence tankmix of nicosulfuron plus bromoxynil HortScience 40 616 619
Diebold, S., Robinson, D., Zandstra, J., O'Sullivan, J. & Sikkema, P. 2003 Sweet corn (Zea mays) cultivar sensitivity to AE F130360 Weed Technol. 17 127 132
Diebold, S., Robinson, D., Zandstra, J., O'Sullivan, J. & Sikkema, P. 2004 Sweet corn (Zea mays) cultivar sensitivity to bentazon Weed Technol. 18 982 987
Dyer, C.D., Bauman, T.T. & White, M.D. 2004 Weed control and soil longevity of KIH-485, acetochlor, dimethenamid, and S-metolachlor Proc. NCWSS 59 63
Mailvaganam, S. 2006 Area, production and farm value of specified commercial vegetable crops, Ontario, 2005 13 July 2006 <www.omafra.gov.on.ca/english/stats/hort/vegsummetric05.html>
Ontario Ministry of Agriculture, Food, and Rural Affairs 2006 Guide to weed control. Publication 75 Ontario Ministry of Agriculture, Food, and Rural Affairs Toronto, Ontario, Canada
O'Sullivan, J. & Bouw, W.J. 1998 Sensitivity of processing sweet corn (Zea mays) cultivars to nicosulfuron/rimsulfuron Can. J. Plant Sci. 78 151 154
O'Sullivan, J., Brammall, R.A. & Bouw, W.J. 1995 Response of sweet corn (Zea mays) cultivars to nicosulfuron plus rimsulfuron Weed Technol. 9 58 62
Robinson, D.K., Monks, D.W., Schultheis, J.R. & Worsham, A.D. 1993 Sweet corn (Zea mays) cultivar tolerance to application timing of nicosulfuron Weed Technol. 7 840 843
Soltani, N., Sikkema, P.H. & Robinson, D.E. 2005b Sweet corn (Zea mays) hybrids responses to thifensulfuron-methyl HortScience 40 1381 1383
Soltani, N., Sikkema, P.H., Zandstra, J., O'Sullivan, J. & Robinson, D.E. 2007 Response of eight sweet corn (Zea mays L.) hybrids to topramezone HortScience 42 110 112