Liquid Formulation of Native Trichoderma spp. for the Biocontrol of Fusarium leaf spot of Bottle Gourd

Abstract

Fusarium leaf spot of Bottle Gourd caused by Fusarium oxysporum is a newly emerging disease in Bangladesh. The present study aimed to develop a Potato-dextrose and yeast molasses-based upgraded Trichoderma liquid formulation for the eco-friendly and sustainable management of the disease. Therefore two native Trichoderma species (Trichoderma HSTUT-6 & Trichoderma HSTUT-8) were used to develop the liquid formulations. In-vitro tests demonstrated the antifungal efficacy of the selected Trichoderma against the isolated and molecular identified Fusarium sp., the causal agent of leaf spot disease. Trichoderma HSTUT-8 showed a maximum zone of inhibition (86.67 %) against F. oxyxporum in the dual culture method followed by Trichoderma HSTUT-6 (82.23 %). Trichoderma HSTUT-8 grown on potato-dextrose-based liquid formulation showed the highest reduction of leaf spot incidence (70.03 % & 73.86 %) and severity (90.19 % and 88.89 %) over control at 80 days after sowing (DAS). This upgraded liquid formulation also showed higher plant height (51.33 & 49 cm), total chlorophyll content (1.88 & 1.84 mg/g fresh weight, respectively), total phenols content in fruits (0.583 & 0.553 mg catechol/100 g fresh weight), number of fruits/plant (13.67 & 14.67, respectively), fruit length (51.33 & 49 cm, respectively), weight (2.24 & 3.093 Kg, respectively), diameter (32.33 & 39.33 cm, respectively), total soluble solids in fruits (6.23 & 5.7 %, respectively), pH (6.8 & 6.64, respectively), moisture content (97.2, 97.63 %) in fruits of Naaz Green and Diana Bottle Gourd. Furthermore, the combined application of potato-dextrose-based Trichoderma liquid formulation showed minimum firmness of fruits (20.53 & 20.33 Kg/m2). The study explored the use of the developed liquid formulation of Trichoderma HSTUT-6 and Trichoderma HSTUT-8 for the field application to control Fusarium leaf spot of Bottle Gourd.