The effect of 2,4-D and 2M-4K on some oil flax varieties grown under different environmental conditions

Paatela, Juhani; Dunham, R. S.

doi:10.23986/afsci.71265

Cited by 2 publications

(3 citation statements)

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“…The present investigation confirms that although many varieties of linseed do not differ appreciably in their susceptibility to chlorinated phenoxyacetic acids there are some varieties which are less tolerant than the majority .Where varieties were common to these experiments and to those of other workers, there was a general agreement on the relative resistance. Thus Dakota and Minerva were amongst the most susceptible (see Table 7), and similar results have been obtained in the United States by Tandon (1949) and Paatela & Dunham (1949). The fact that the most susceptible varieties of Exp.…”

Section: Discussionsupporting

confidence: 84%

Studies in selective weed control V. The control of weeds in linseed by chlorinated phenoxyacetic acids

Holly

Blackman

1954

J. Agric. Sci.

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Between 1946 and 1950 multifactorial field experiments were carried out to determine the potentialities and effectiveness of chlorinated phenoxyacetic acids for the selective control of weeds in linseed (oil flax). The initial experiments of 1946 demonstrated that treatment with sodium 2-methyl-4-chlorophenoxyacetate led to considerable increases in the yield of seed through a reduction of the weed population and the consequent decrease in weed competition.The subsequent experiments were undertaken on relatively weed-free crops so that the direct effects on the crop of compound, formulation, and stage of growth at the time of application could be investigated along with differences in varietal response. Amongst the observations made were time of flowering, straw length, the yield of seed, capsule production, seeds per capsule and the weight, oil content, protein content and germination capacity of the seed.At similar dosages sodium methylchlorophenoxyacetate is less phytotoxic than sodium 2, 4-dichlorophenoxyacetate while the parent acid and particularly the ethyl ester of the dichloro - compound are much more injurious. With sodium methylchlorophenoxyacetate the tolerance is greatest between the post-cotyledon stage and a height of 20–25 cm.; within this range of plant development dosages up to 3·5 lb./acre have no adverse effects on the yield of seed. Treatment within 2–3 weeks of flowering delays flowering and reduces the seed weight. When dichloro-compounds are employed there are additional effects, such as the formation of abortive capsules or a reduction in the number of seeds per capsule. Under some conditions the oil content and the germination capacity of the seed is depressed but the protein content is increased.

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Section: Discussionsupporting

confidence: 84%

Studies in selective weed control V. The control of weeds in linseed by chlorinated phenoxyacetic acids

Holly

Blackman

1954

J. Agric. Sci.

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“…A similar difference has already been reported for Unseed (oil flax) by Blackman et al (1949), Paatela (1949), Paatela & Dunham (1949) and Aberg, Hagsand & Vaartnou (1949). Since sodium methyl-chlorophenoxyacetate is equally or more toxic than sodium dichlorophenoxyacetate to a variety of annual weeds (e.g.…”

Section: Discussionsupporting

confidence: 79%

“…A similar effect has been reported with linseed straw by Paatela (1949). At present only a tentative explanation can be put forward to account for this increase in straw production.…”

Section: Discussionsupporting

confidence: 73%

Studies in selective weed control IV. The control of weeds in fibre flax

1951

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During the period 1942–50 some thirty-seven multifactorial field experiments have been carried out to determine the conditions under which weeds in fibre flax can be selectively controlled by herbicides. In order to assess the direct effects of treatment on flax, some experiments have been undertaken in weed-free crops, while others have been sited in weed-infested crops so that the increases in productivity following on weed suppression could be evaluated.In almost all experiments, the total crop weight, the yield of de-seeded straw and the amount of scutched fibre per plot were determined, while in a proportion seed yield was also measured. Where weeds were present, counts were made to establish the degree of control.The preliminary experiments demonstrated that sulphuric acid, ammonium sulphamate and ammonium thiocyanate were far too toxic to flax. An examination of a range of cupric salts suggested that the most promising compound was cupric chloride, while of the formulations of dinitro-o-cresol investigated only the sodium salt appeared to be sufficiently selective. It was also found that in terms of fibre production sodium 2-methyl-4-chlorophenoxyacetate was less toxic than sodium 2:4-dichlorophenoxyacetate. In consequence, the bulk of the investigations have related to determining the optimal conditions for the use of cupric chloride, sodium dinitro-o-cresylate and sodium methylchlorophenoxyacetate.For all three compounds it has been observed that flax is least liable to injury at a height range of 2–6 in. There are limitations to the amounts which can be safely employed, namely, 20 lb. of cupric chloride or 6 lb. of sodium dinitro-o-cresylate applied in 100 gal. of spray solution per acre. With sodium methyl-chlorophenoxyacetate the corresponding limit is 1 lb./acre, and the evidence suggests that the crop may be injured if the volume of application is reduced below 25 gal./acre.Within these limitations of concentration volume and stage of development of the crop, the suppression of annual weeds has led to significant increases in the yield of straw, seed and scutched fibre. Larger gains resulted from the use of sodium methyl-chlorophenoxyacetate and sodium dinitro-ocresylate. This superiority over cupric chloride is in part attributed to the wider range of weed species which are killed by the two sodium salts and in part due to the greater liability of crop damage if the limits on amount and time of application are not strictly observed.The results have also clearly established that for fibre flax the weight of total crop, the yield of straw, the amount of seed or plant height cannot be taken as reliable criteria for the evaluation of herbicides, for while all these may be little affected by treatment yet there may still be large reductions in the amount of recoverable fibre. A preliminary anatomical examination of the internal changes in the stems of flax has shown that when treatment with dichlorophenoxyacetic acid is delayed, a marked but localized curvature of the stem results and in this zone fibre formation is abnormal: thus breakages either during pulling or processing may occur at this point of weakness.

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The effect of 2,4-D and 2M-4K on some oil flax varieties grown under different environmental conditions

Cited by 2 publications

References 1 publication

Studies in selective weed control V. The control of weeds in linseed by chlorinated phenoxyacetic acids

Studies in selective weed control V. The control of weeds in linseed by chlorinated phenoxyacetic acids

Studies in selective weed control IV. The control of weeds in fibre flax

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