Hot water treatments to control black rot caused byAlternariasp. in yellow pitahaya (Selenicereus megalanthus)

Abstract

Postharvest fungal infections in yellow pitahaya (Selenicereus megalanthus) cause the majority of losses during export. Synthetic fungicides are the main strategy for disease control, but constraints associated with the use of this kind of products have led to the search for alternative methods to reduce fungal infections. In this research, the efficacy of hot water dips at several temperatures and times for the control of black rot of yellow pitahaya was assessed by measuring lesion diameter on fruit pre-inoculated with Alternaria sp. The results showed that both treatments 50°C for 2 min and the fungicide imazalil (0.4 g L-1) significantly, reduced lesion diameter (62.8 and 71.4% of reduction, respectively) after 21 days of storage at 12°C compared with control fruit (pre-inoculated with Alternaria sp. and non-treated). The hot water treatment had no significant effect on fruit physiological quality, with similar results for color, firmness, titratable acidity and solid soluble content (SSC) were obtained on fruit treated with hot water and fruit treated with chemical fungicide. In conclusion, these results indicated that dips in hot water may provide a non-chemical alternative treatment for postharvest control of black rot caused by Alternaria sp. in yellow pitahaya. It is a residue-free method, respectful with human health and environment.