Evaluation of Fungicides to Control Loquat Scab Caused by Fusicladium eriobotryae

Abstract

Loquat scab caused by Fusicladium eriobotryae is the main disease affecting the loquat crop. The fungus can infect leaves and fruits, reducing the marketable quality of the latter. The efficacy of 13 fungicides against F. eriobotryae was evaluated in vitro by testing their effect on mycelial growth and conidial germination. Boscalid, chlorothalonil, didecyldimethyl ammonium chloride, and pyraclostrobin were able to reduce both conidial germination and mycelial growth of F. eriobotryae. Moreover, a growth chamber experiment was conducted to determine the pre- and post-infection activity of five selected fungicides. Difenoconazole and pyraclostrobin applications resulted in relative disease severity (RDS) values lower than 5%, even when applied 7 days before or after the inoculation. Boscalid and mancozeb applied before F. eriobotryae inoculation resulted in RDS values lower than 15%, whereas values up to 20% of RDS were obtained with copper oxychloride. Results indicate that the fungicides currently recommended in southeastern Spain against loquat scab provide adequate disease control, and new active ingredients could be added to the present management strategies. Accepted 7 May 2014. Published 27 July 2014.