Reduced cost approached to herbicide and fungicide use on cereals in Scotland

Summary

Sector:
Cereals & Oilseeds
Project code:
PR104
Date:
01 August 1989 - 31 July 1992
Funders:
AHDB Cereals & Oilseeds.
AHDB sector cost:
£122,928 From HGCA (Project No. 0036/2/88)
Project leader:
N M Fisher, J Gilmour and S J P Oxley SAC-Edinburgh, D H K Davies SAC Crop Systems Department, S J I Holmes SAC-Auchincruive S J Wale, and G P Whytock SAC-Aberdeen

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About this project

Abstract

Many trials took place in the arable areas of Scotland for harvest in the years 1990 to 1992. The fungicide trials used a range of varieties and tested a range of programmes with low dose fungicide mixtures on winter wheat and spring barley. The herbicide trials used a range of products or tank mixes, alone or in sequence and at a range of doses.

On winter wheat, a half dose programme based on prochloraz products for the early sprays and a triazole-protectant mix for the later sprays was consistently cost effective for Hornet and Riband. A low dose of morpholine was added when mildew or yellow rust threatened. For Hornet, this was estimated to be more cost-effective than the full dose programme in 94% of the situations represented by the trials. For Apollo, a cheaper half dose programme primarily aimed at mildew was estimated to be more cost effective than the full dose in 70% of Scottish situations.

For spring barley, a quarter dose mixture of fenpropimorph with either propiconazole or flusilazole and applied twice was more cost effective than two full doses of morpholine in 64 to 97% of situations, depending on variety. Success of the low dose programme depends on the applications being made early in the development of mildew.

Excellent broad-leaved weed control in winter cereals was achieved by a quarter dose of a product with diflufenican or pendimethalin applied in the autumn, followed by a quarter dose of mecoprop (or mecoprop P) in spring. The second dose was not needed in more than half of the trials. The quarter dose sequence was successful in 82% to 92% of situations.

A high level of weed control was less easily achieved for spring barley. The most effective products tested were a tank mix of metsulfuron-methyl with mecoprop and a proprietary mix of ioxynil, bromoxynil and fluroxypyr. These had a success rate of 55% at the quarter dose but did not always leave a clean crop when the full dose was used. Despite being weedy, the highest yields of spring barley were at the quarter or half dose.

The results reported here have had a major influence on advice given to farmers by SAC and other Advisers in Scotland and our Current Advice is summarised.

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