Combinations of strobilurin fungicides and acibenzolar (Bion) to reduce scab on passionfruit caused by Cladosporium oxysporum

Abstract

Field applications of the strobilurin group of fungicides were shown to provide effective control of fruit scab and alternata spot of passionfruit cv. Supersweet 1. An anti-resistance program incorporating industry standard fungicides (copper oxychloride, mancozeb, iprodione), azoxystrobin and acibenzolar resulted in the most improved level of control, and significantly reduced the severity and incidence of scab by approximately 30% and 80%, respectively, compared with the industry standard fungicides. Tank-mixing acibenzolar with azoxystrobin or the industry standard fungicides, significantly improved scab but not control of alternata spot disease. In growth cabinet studies, acibenzolar was also shown to provide significant protection of seedling plants when applied on the same day or 4 days prior to challenge inoculation with the scab pathogen, Cladosporium oxysporum. This protection was shown to last at least 25 days.