Selectivity of Nitrofen and Oxyfluorfen BetweenPortulaca oleraceaEcotypes and Two Cabbage(Brassica oleraceavar.capitata)Cultivars

Abstract

A collection of common purslane(Portulaca oleraceaL.) ecotypes from various locations around the world was assembled at the University of Illinois. Applications of nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether) to the various ecotypes showed that 3 of the 26 ecotypes [India, Mexico, and Florida (Sanford)] exhibited some degree of tolerance. This marginal tolerance rapidly disappeared as the rate of nitrofen increased beyond 0.56 kg/ha. All of the ecotypes tested were susceptible to applications of oxyfluorfen [2-chloro-2-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene]. Oxyfluorfen was toxic to common purslane plants at rates as low as 5 g/ha. Treatment of ‘Hybelle’ (tolerant) and ‘Rio Verde’ (susceptible) cabbage(Brassica oleracevar.capitataL.) cultivars with 3.36 kg/ha nitrofen reduced plant fresh weight to 82% and 62%, respectively, of control. Oxyfluorfen at 0.15 kg/ha reduced fresh weight to 60% and 27% for Hybelle and Rio Verde, respectively. Applications of nitrofen at 3.36 kg/ha reduced plant fresh weight in Hybelle the same amount as 100 g/ha oxyfluorfen and 70 g/ha in Rio Verde.

CHANGES IN STOMATAL CONDUCTANCE AND TURGOR PRESSURE IN Gossypium hirsutum L. IN RESPONSE TO FOLIAR APPLICATION OF FOUR HERBICIDES

“…Any of a wide range of herbicides that disrupt steps in basic cell metabolism is expected to cause damage to the cells, leading to loss of turgor. Gorske and Hopen (1978), have showed that the two herbicides nitrofen and oxyflurofen decreased the water potential in two varieties of cabbage by about two bars, whereas O , Looney and Fry (2005) have reported that a novel herbicide oxaziclomefone inhibited cell expansion in maize without affecting turgor pressure or wall acidification. Many physiological, biochemical and growth parameters were negatively affected by foliar application of five herbicides in cotton and maize seedlings (El Tahir, 2010).…”

Effect of Pendimethalin and Oxyfluorfen Herbicides on Relative Water Content in Leaves of Zea mays l. Seedlings.

“…Five herbicides were reported to decrease the turgor pressure in cotton and maize seedlings (El Tahir, 2010). Gorske and Hopen (1978) showed that the two herbicides nitrofen and oxyfluorfen lowered the water potential in two varieties of cabbage by about two bars.…”

Effect of Temperature and Cultivar on the Response of Broccoli and Collard (Brassica oleracea) to Oxyfluorfen

“…Because these crops are frequently direct-seeded, the ability to apply oxyfluorfen preemergence (PRE) or postemergence (POST) would increase its utility. These methods of applying oxyftuorfen have been evaluated by several researchers but were usually reported to cause unacceptable crop injury (Bhowmik and McGlew 1986;Farnham and Harrison 1997;Gorski and Hopen 1978;Grabowski and Hope 1984;Harrison and Farnham 1998;Herbst andDerr 1990a, 1990b;Johnson et aI., 1992). Herbst andDerr (1990a, 1990b) reported that PRE oxyftuorfen at 0.14, 0.28, and 0.56 kg/ha caused unacceptable delays in broccoli harvest and reduced stands and yields.…”

“…POST oxyfluorfen provides good weed control in broccoli and cabbage (Farnham and Harrison 1997;Gorski and Hopen 1978;Grabowski and Hopen 1984;Herbst and Derr 1990a). However, in some instances, the herbicide caused crop injury and reduced yields (Farnham and Harrison 1997;Grabowski and Hopen 1984).…”

“…However, in some instances, the herbicide caused crop injury and reduced yields (Farnham and Harrison 1997;Grabowski and Hopen 1984). Differences between cultivars in response to POST application of oxyfluorfen have been observed for cabbage and broccoli, but crop response was not always consistent across locations or seasons (Farnham and Harrison 1997;Gorski and Hopen 1978). Gorski and Hopen (1978) reported that cabbage cultivars varied in tolerance to POST oxyfluorfen.…”