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Influence of Ammonium Thiocyanate on Scorching and Control of Bracken (Pteridium aquilinum) by Amitrole

Published online by Cambridge University Press:  12 June 2017

G. T. Cook ,
N. H. Stephen  and
H. J. Duncan
G. T. Cook
Affiliation:
Agric. Chem. Dep., Univ. of Glasgow, Glasgow G12 8QQ, Scotland
N. H. Stephen
Affiliation:
Agric. Chem. Dep., Univ. of Glasgow, Glasgow G12 8QQ, Scotland
H. J. Duncan
Affiliation:
Agric. Chem. Dep., Univ. of Glasgow, Glasgow G12 8QQ, Scotland
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Abstract

The field performance of amitrole (3-amino-s-triazole) formulations containing a number of additives was tested on bracken [Pteridium aquilinum (L.) Kuhn var. aquilinum]. All formulations that did not contain thiocyanate produced severe foliar scorching within 72 h of spraying. The following season, control was relatively poor (63 to 77% reductions in frond density). The formulation of amitrole with sodium iodide produced particularly severe scorching followed by a nonsignificant reduction in frond density (2%) the following season. Formulations containing ammonium thiocyanate (molar ratios of 1:0.5, 1:0.75, 1:1, and 1:1.25 amitrole:ammonium thiocyanate) greatly reduced this foliar scorching, and control the following season was of the order of 94 to 97% in all cases. Translocation was proposed as being the limiting factor in control, ammonium thiocyanate increasing translocation by preventing scorching and hence decreasing decomposition in the foliage. To investigate scorching further, a bioassay, which consisted of floating bracken leaflets on amitrole solutions, was developed. The commercial 1:1 molar ratio of amitrole:ammonium thiocyanate may not be optimum for all conditions. Other additives were tested and cyanide and hexacyanoferrate (II) were found to be very active scorch inhibitors.

Keywords

Translocationfree radical inhibitorscyanidehexancyanoferrate (II)
Type
Research Article
Information
Weed Science , Volume 29 , Issue 2 , March 1981 , pp. 196 - 200
Copyright
Copyright © Weed Science Society of America 

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References

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