EFFECT OF TILT ON SEVERITY OF SPOT-TYPE NET BLOTCH, GRAIN YIELD AND YIELD COMPONENTS IN BARLEY

Abstract

Spot-type net blotch, incited by Pyrenophora teres f. maculata has become widespread in Saskatchewan. This study was conducted to evaluate the effect of the fungicide Tilt (propiconazole) on the severity of spot-type net blotch, grain yield and yield components in spring barley. The susceptible cultivar Elrose was subjected to five schedules of foliar application of Tilt at Medstead, Shellbrook and Saskatoon, Saskatchewan in 1985 and 1986. The moderately susceptible cultivar Argyle was included in the experiments conducted in 1986. Results show that Tilt controlled spot-type net blotch in Elrose. However, the effective period was limited. A single application did not control spot-type net blotch in cases with rapid disease development. Application of Tilt at Zadoks growth stages 31 and 49 would be required to provide reliable control in a susceptible cultivar. Control of spot-type net blotch increased grain yield. A single application of Tilt increased grain yield up to 23% over the untreated control. In most cases, a double application of Tilt did not increase grain yield over a timely single application. Increased grain yield was associated with increased kernel weight. The correlation coefficient between grain yield and kernel weight ranged from 0.82 to 0.88. Tilt had no effect on a healthy crop of Elrose and the moderately susceptible cultivar Argyle.Key words: Pyrenophora teres f. maculata, Hordeum vulgare L., propiconazole, barley