Effect of partial defoliation on Cylindrocarpon destructans infection of grapevines

Abstract

Oneyearold grapevines of Sauvignon blanc grafted to rootstocks 10114 or Schwarzmann were used to evaluate the effects of partial defoliation and inoculation with C destructans on disease severity incidence and dry weight accumulation Assessment 8 months after treatments showed that disease incidence was not affected by the defoliation treatments However disease severity was significantly highest for the highly defoliated plants (P0043) Incidence and severity were similar for Schwarzmann (293 and 84 respectively) and 10114 (310 and 149 respectively) Root dry weight was affected by the defoliation treatments (P0000) being significantly lower in the highly defoliated plants than the moderately defoliated and undefoliated plants (156 185 and 199 g respectively) The practice of leaf removal in young vines clearly needs to be managed when black foot is a recognised risk factor for newly planted vineyards