Temperature Effect on Difenzoquat Phytotoxicity

Abstract

The phytotoxicity of difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) applied to the three-leaf stages of hard red spring wheat (Triticum aestivumL. ‘Waldron’ and ‘Era’), barley (Hordeum vulgareL. ‘Beacon’) and wild oat (Avena fatuaL. ♯ AVEFA) grown under constant, fluctuating, or alternating day-night temperatures was determined in controlled environment chambers. Difenzoquat injury to wild oat and Era wheat was greater at a constant 20 or 30 than at 10 C; however, injury to Waldron wheat was similar at 10, 20, and 30 C. Difenzoquat caused only slight injury to barley, and injury was similar at all temperatures. In Era wheat, selectivity of difenzoquat for wild oat was maximum with a 10-C night temperature in an otherwise 30-C-temperature environment; in Beacon barley selectivity was maximum with 3 or more days of 20- or 30-C posttreatment temperature; and in Waldron wheat selectivity was not adequate at any of the temperatures studied.

Glyphosate Activity in Potato (Solanum tuberosum) Under Different Temperature Regimes and Light Levels

“…At low temperature (13/4 C), only a third (20 x 10 3 DPM) as much total 14 C-glyphosate was found in plant parts as at the high temperature (65 x 10 3 DPM). Decreased phyto toxicity at lower temperature has also been observed with difenzoquat applied to leaves of wild oat (Avena fatua L. # AVEFA) grown at 10C compared to plants grown at 20 and 30 C (16). The decreased absorption we observed was not related to differences in leaf structure between plants grown in the two temperature regimes, since the leaves to which glyphosate was applied were formed in the green house before the plant was placed into the growth chamber.…”

Influence of temperature on the activity of AC 222,293 against Avena fatua L. and Alopecurus myosuroides Huds.

“…The more common trend of increased activity with higher temperature has been reported for a variety of herbicides e.g. fluazifop-butyl (Kells, Meggitt & Penner, 1984); difenzoquat (Miller, Nalewaja & Dobranski, 1984); acifluorfen (Wills & McWhorter, 1981); pyrazon (Koren & Ashton, 1973).…”

Environment and Bromoxynil Phytotoxicity

“…Environmental conditions at application are known to influence the efficacy of many postemergence herbicides. Postemergence herbicide phytotoxicity was generally influenced more by environment after than before treatment (1,4,5,6). High temperature at or after treatments has increased the phytotoxicity of most herbicides (4,6,7,9).…”

“…Postemergence herbicide phytotoxicity was generally influenced more by environment after than before treatment (1,4,5,6). High temperature at or after treatments has increased the phytotoxicity of most herbicides (4,6,7,9). However, barban (4-chloro-2-butynyl 3-chlorophenylcarbamate) was more phytotoxic at low than at high tem-peratures after treatment (5).…”