Sodium bicarbonate enhances efficacy of Trichoderma harzianum DGA01 in controlling crown rot of banana

Abstract

The efficacy of Trichoderma harzianum strain DGA01, sodium carbonate (SC), sodium bicarbonate (SBC) and sodium hypochlorite (SH) applied alone or in various combinations was evaluated in vitro against the most important postharvest pathogens of banana such as Lasiodiplodia theobromae, Thielaviopsis paradoxa, Colletotrichum musae, and Fusarium verticillioides. Trichoderma harzianum DGA01 was compatible with salts at a concentration of 1 % (w/v) as manifested by normal mycelial growth. The efficacy of the fungal antagonist in vitro was enhanced by 10.16–13.06 % in controlling mycelial growth of crown rot pathogens with the addition of salts. After a postharvest dip of fruit for 30 min in 106 conidia of DGA01/mL of 1 % SBC, the incidence of crown rot was reduced by 92 %, but DGA01 combined with SC or SH had no additive effect in controlling crown rot. Thus, DGA01 and SBC was the best combination for crown rot control, with an efficacy similar to synthetic fungicides, and maintained the overall quality of banana even at conditions favourable for the pathogens (22–25 °C, 90–95 % relative humidity).