In Vitro and In Planta Botanical Control of Banana Postharvest Disease Causing Fungi

Postharvest brown spot (Lasidiplodia theobromae) and crown rot (caused by a pathogen complex) are the most important postharvest issues in Bangladesh. Research information regarding banana postharvest disease control is limited in Bangladesh. Thus, this research aimed to identify the causal agent, and tested certain botanical extracts for their antifungal properties to reduce banana postharvest infections. These two symptoms of local banana provided 37 fungal isolates through standard isolation method. Later, L. theobromae, Colletotrichum fructicola, and Fusarium equiseti were identified morphologically and molecularly. Lasidiplodia theobromae (Lt1) was selected for further disease control studies as this pathogen causes both crown rot and brown spot simultaneously. For the antifungal efficacy tests, several botanical extracts (from Aloe vera, garlic bulb, onion bulb, and moringa leaf t) were chosen based on their local availability and previous research findings (on other fruit). Among the botanicals, Aloe vera + Garlic (0.78 cm), Aloe vera (3.08 cm), and Garlic (0.53 cm) successfully reduced the fungal growth compared with the untreated control (4.78 cm) in vitro. Among these botanicals, Aloe vera (250 mL/L) + Garlic (50 mL/L) successfully reduced both brown spot and crown rot in planta at 11 days after treatment. This botanical combination did not have an adverse effect on the physiochemical properties of banana such as weight, color, firmness, and TSS. This study suggests Aloe vera and garlic as nonchemical green fruit coat to reduce the postharvest fruit diseases and ensure consumer safety.