Potassium silicate as a fungicide enhancer against Botrytis cinerea in blackberry

Abstract

Blackberry gray mold, induced by Botrytis cinerea, is a fruit disease that causes important economic losses. The present study evaluated nine fungicides belonging to different chemical groups, alone and in combination with potassium silicate, using the dose recommended on the label for the control of B. cinerea in the field. The incidence and severity of the disease were evaluated, as well as the degrees Brix, silicon concentration, and yield. The experiment was carried out twice. Incidence and severity percentages were converted to area under the disease progress curve (AUDPC). Combined with potassium silicate, the fungicide azoxystrobin significantly reduced incidence and severity, showing the lowest percentages in the last evaluation of these variables. In the first repetition, the incidence and severity values were 4% (AUDPC = 1320) and 0.1% (AUDPC = 298.5), respectively. In the second, 3% (AUDPC = 1099) and 0.1% (AUDPC = 214.5) respectively. The concentration of soluble solids and fruit yield increased (12.4 and 13.6 t ha-1 in the first and second repetition, respectively). The results indicate that potassium silicate enhances the effect of fungicides under field conditions and can thus be considered a management alternative against the gray mold disease in blackberries.