Evaluation and comparison of biocontrol and conventional fungicides for control of postharvest potato tuber diseases

Two biocontrol fungicides (Bacillus subtilis and Bacillus pumilus) and three conventional fungicides (phosphorous acid, azoxystrobin and hydrogen peroxide) were evaluated in two storage trials over 2 years for efficacy in suppressing tuber infection caused by Phytophthora infestans, Phytophthora erythroseptica, Pythium ultimum and Fusarium sambucinum. A chip-processing cultivar, FL 1879, stored at 10 °C was used for the two trials. Tubers were inoculated followed by treatment with the fungicides prior to storage. Disease incidence was assessed after 120 d in storage. The biocontrol fungicides had limited control of the storage pathogens compared to the conventional fungicides. Phosphorous acid, hydrogen peroxide and azoxystrobin were moderately effective in controlling diseases caused by the oomycete pathogens. Although none of the products evaluated completely controlled the storage diseases, the conventional fungicides showed a higher potential for suppressing tuber infection in storage than the biocontrol fungicides. Use of these biocontrol fungicides could be integrated with other management strategies.

Highlights► There is a shortage of postharvest fungicides to control potato diseases in storage. ► In these studies, the biocontrol fungicides were to some extent as effective as the conventional fungicides. ► Both offered limited broad-spectrum control of potato storage diseases. ► Use of these products should be integrated with other management strategies.