Benefit of fungicide treatment after trunk renewal of vines with different types of esca necrosis

Abstract

Vines cv. Trebbiano d'Abruzzo grown in three vineyards located in Teramo Province, Abruzzi, Italy, severely affected by esca proper, were subjected to trunk renewal and thereafter treated with triazoles and fosetyl Al fungicides, applied either by trunk injection via syringe, or by ground injection via injector pole. Trunk renewal, by cutting the trunk, made it possible to determine the extent and type of wood deterioration on the residual trunk portion, where it was found that rotted and discoloured wood often still remained. Fungicide treatment was begun in 1995, when trunk renewal was performed, and was continued until 1998; after this the vines continued to be monitored for a further 4 years until 2002. In 2002, vines that had received trunk injections after trunk renewal were in better vegetative condition than vines without such injections, with full yield and lower mortality. Cyproconazole was particularly effective when trunk injected, but was not effective when injected into the ground. A possible explanation for this is given. Moreover the effect that the severity of the wood necrosis observed at the time of trunk renewal had on treatment effectiveness was evaluated. The current lack of similar trials and studies in other vineyards makes standardisation of control methods difficult; any positive effects may have been due to concurrent factors such as cultivar vigour, or peculiar environmental or cultural conditions.