ASSESSMENT OF LOSSES CAUSED BY SEPTORIA GLUME BLOTCH OF TRITICALE USING THE IMPROVED SINGLE-TILLER METHOD

Septoria glume blotch of triticale induced by Leptosphaeria nodorum E. Muller is the major foliar disease in Tras-os-Montes (NE Portugal) an d can cause considerable damage under the right weather and crop condi tions. Because of erratic occurrence of the disease, epidemics of glum e blotch were artificially created by spraying spores of the pathogen. Single affected tillers of hexaploid triticale cv. Corgo and unaffect ed neighbours were tagged and the severity of the disease recorded at early milk stage. Tagged tillers were recovered and grain weight and n umber of grains per ear were processed. Considering the number of grai ns and severity, the percentage of yield variability being explained b y septoria was improved to 67.2% of the variation. Previous analysis t aking into account severity explained only 4.6% of the variation.