Barley net blotch: Survey of sensitivity to DMI Fungicides


Cereals & Oilseeds
Project code:
01 April 1996 - 30 June 1996
AHDB Cereals & Oilseeds.
AHDB sector cost:
£12,579 From HGCA (Project No. 0021/01/96)
Project leader:
T Locke ADAS Rosemaund



About this project


In a survey of 30 winter barley crops during 1996 isolates of Pyrenophora tereswere found to be less sensitive to propiconazole and prochloraz than in 1991. A close correlation was found between the sensitivity of isolates to propiconazole and flusilazole. Positive correlations were also found between all four demethylation inhibitory (DMI) fungicides tested, propiconazole, prochloraz, expoxiconazole and flusilazole.

Pathogen sensitivity was lower following the use of two or three DMI sprays in the sampled crop, rather than where one such spray had been used. Lower sensitivity was also found in crops which followed barley rather than another type of crop. In fifteen crops net blotch levels were recorded at growth stage 71 -73 and reduced sensitivity occurred in those crops with the lowest disease levels. There was no significant difference in sensitivity levels between samples from different parts of England and from Scotland.