Evaluation of fungicides for the control of Botryosphaeria corticola on cork oak in Catalonia (NE Spain)

Botryosphaeria canker of cork oak (Quercus suber L.), caused by Botryosphaeria corticola, is a well-known factor contributing to the decline of this forest species and is a serious disease in the main cork-producing countries of the Western Mediterranean basin. In this work, fungicides with the potential for controlling the disease were selected using a combination of in vitro tests and field trials. Fourteen fungicides in different chemical families were tested in vitro to evaluate their effect on inhibition of mycelial growth. The most effective fungicides were benomyl, carbendazim, cyprodinil + fludioxonil, thiabendazol and thiophanate-methyl; these compounds were then further tested under field conditions. In the field trials, carbendazim and thiophanate-methyl were the most effective fungicides, as shown by efficacy indices, in reducing debarked trunk surface affected by cankers (76% and 50–65%, respectively). These results suggest that the occurrence of Botryosphaeria canker on cork oak can be reduced effectively with the application of selected fungicides after cork removal from the trees.