Experiments on the control of barley smut Ustilago hordei (Pers.) (Kell.) were carried on for four years at the Paine Plant Breeding Station and during two years at the Chillán Plant Breeding Station. The field plots were laíd out and the results analyzed statistically according to Fisher's methods.
The following products were tested; Abavit, copper carbonate, formaldehyde, Hydrit, Mercysol and Tillantina. The fungicidal power of each was estimated by counting the number of smutted heads of barley in each plot.
Abavit and Hydrit gave perfect smut control and the control was good with Mercysolevery year except one. Tillantina was only fair while copper carbonate was but slightly better than the check. The results with formaldehyde were very erratic, both for years and for localities.
A highly significant correlation of the fungicidal power of the products was found between the results at the Paine Plant Breeding Station for 1941 and for 1942, and between the results at Paine and at Chillán in 1942.
Even though there were great differences in fungicidal power hetween treatments, there were no significant differences in the yield of harley.

1 Ing. Agr. Del Departamento de Genética y Fitotecnia