“…Herbicide efficacy is affected by the many complex interactions involving environmental conditions (weather and soil, both before and after application) (Hallgren, 1989; Caseley, 1990; Kudsk & Kristensen, 1992; Minkey & Moore, 1996, 1998; Lundkvist, 1997) and plant factors (species, stage of development, competitive ability of the crop, etc.) (Rioux et al ., 1974; Lemerle & Verbeek, 1995). Particular variables of importance include soil moisture stress (Boydston, 1990; Dastgheib et al ., 1990; Dickson et al ., 1990; Lemerle & Verbeek, 1995), nitrogen deficiency (Dickson et al ., 1990), temperature, light, wind, humidity and rainfall (Muzik, 1975; Doran & Andersen, 1976; Coupland, 1983, 1984; Merritt, 1984; Nalewaja & Woznica, 1985; Jensen & Kudsk, 1988; Devine, 1989; Caseley, 1990; Wicks et al ., 1993; McMullan, 1994; Madafiglio et al ., 2000).…”