Acibenzolar-S-methyl induces protection against the vascular wilt pathogen Fusarium oxysporum in cape gooseberry (Physalis peruviana L.)

Vascular wilt caused by Fusarium oxysporum is one of the most devastating diseases that affect cape gooseberry plants. In order to contribute to its management, the objective of this work was to evaluate the plant activator acibenzolar-S-methyl (ASM) as a reducer of vascular wilt symptoms in cape gooseberry. Sixty-day-old plants were sprayed twice with eleven concentrations of ASM ranging from 10 to 200 mg L⁻¹, respectively. The phytotoxic effect was assessed for a period of eight weeks. The appearance of symptoms such as stunting, a decrease in the shoot and roots dry weight, leaf malformation and defoliation was associated with the ASM concentration. The two lowest concentrations of ASM assessed (10 and 20 mg L⁻¹) were selected to evaluate their effectiveness against F. oxysporum in greenhouse conditions. Both concentrations reduced vascular colonization and necrosis generated by seven isolates of F. oxysporum, and in consequence, the area under the disease progress curve (AUDPC) decreased significantly during the eight weeks of evaluation. These results suggest that ASM induces resistance to F. oxysporum in cape gooseberry under greenhouse conditions.