An integrated approach with Trichoderma harzianum DGA01 and hot water treatment on control of crown rot disease and retention of overall quality in banana

Abstract

A biological control of crown rot disease of banana fruit was analysed using an integrated approach combining hot water treatment and Trichoderma harzianum strain DGA01. Treated fruits were stored at 22–25 °C and 90–95% relative humidity for 2 weeks. The bioefficacy of fungal antagonist in vitro towards crown rot-causing pathogens, namely Lasiodiplodia theobromae, Thielaviopsis paradoxa, Colletotrichum musae and Fusarium verticillioides, was enhanced by 11.41% following hot water treatment (50 °C, 20 min). DGA01 germinated on the fruit 48 h after inoculation and parasitised the pathogen. Postharvest application showed that hot water treatment and conidial suspension of DGA01 (106 ml−1) applied singly performed significantly better than the untreated control in reducing the incidence of crown rot, but were not as effective as the fungicide. The combination of hot water treatment and DGA01 gave 93% control of fruit decay which was comparable with fungicide treatment of 95%. The quality of fruit was markedly improved in hot water treatment + DGA01 as compared to those dipped in fungicide solution. The inconsistencies of single treatments, by DGA01 or hot water dips, in controlling crown rot such as variation in severity of disease among treatments and within a treatment, were lessened by dipping the fruit in DGA01 conidial suspension following hot water treatment.