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A FIELD STUDY OF THE FACTORS AFFECTING THE HERBICIDAL ACTIVITY OF IOXYNIL AND BROMOXYNIL AND THEIR TOLERANCE BY CEREALS
Author(s) -
TERRY H. J.,
WILSON C. W.
Publication year - 1964
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1964.tb00289.x
Subject(s) - stellaria media , bromoxynil , agronomy , weed , biology , crop , weed control , proline , chemistry , horticulture , amino acid , biochemistry
Summary. The herbicidal activity and the tolerance of winter and spring cereals to ioxynil (4‐hydroxy‐3,5‐diiodobenzonitrile)and bromoxynil(3,5‐dibromo‐4‐hydroxybenzonitrile) as alkali metal and ammonium salts, have been determined in field experiments. Both compounds controlled most of the important weeds of cereals at doses between 3 and 8 oz a.i./ac. In seedling grass crops, where weeds were influenced less by crop competition, the effective dose range was 6–8 oz/ac. Some species normally resistant to the phenoxyalkanoic acid herbicides, including Stellaria media, Tripleurospermum marilimum and some Polygonum spp. were controlled by these herbicides. Ioxynil was generally more active than its dibromo analogue, particularly against Stellaria media . The activity of both compounds was improved by the addition of a wetting agent (0–02% sodium dinonyl sulphosuccinate) but activity was not influenced by changes in volume rate over the range 18–65 gal/ac. Perennial weeds were not affected by the doses needed for the control of annual weeds and rates of 16 oz/ac and above were necessary for the control of Cirsium arvense and Sonchus arvensis . The factors most likely to affect cereal tolerance are growth stage of crop and the addition of wetter to the spray solution. Neither ioxynil nor bromoxynil significantly affected grain yields when applied to spring and winter wheat, spring barley and oats at two to four times the rate necessary for weed control. On a total of five varieties of spring wheat and six varieties each of spring barley and oats applications of both compounds at doses up to 32 oz/ac caused only temporary and superficial leaf scorch. In only two out of twenty‐five experiments was there more than slight scorch at doses below 16 oz/ac and these two cases do not significantly detract from the evidence of the high crop safety margin of these compounds. Étude en plein champ des facteurs influençant l'activité herbicide de l'ioxynil et da bromoxynil et la tolérance des céréales à ces deux herbicides