Preparation of Water-Soluble Formulations From Industrial Clove Waste and Their Antifungal Activities Against Powdery Mildew (Oidium mangiferae) and Post-Harvest Anthracnose (Colletotrichum gloeosporioides) of Mango

Abstract

Industrial clove waste (ICW), a plant-based byproduct of the clove processing industry, contains various chemical compounds with potential antifungal, insect-repellent and antimicrobial properties. The chemical composition of industrial clove waste was analysed using GC-MS, which revealed benzyl benzoate as the major constituent (96.30%). Water-soluble formulations were prepared by mixing industrial clove waste with different adjuvants. Among these, three formulations—ICW (50%) + Tween 80 (30%) + water (20%), ICW (60%) + Tween 80 (20%) + water (20%) and ICW (70%) + Tween 80 (10%) + water (20%) were found to be water-soluble. The ICW 50% water-soluble formulation met the WHO specifications for pesticide emulsifiable concentrate formulations in terms of physical parameters and was selected for further studies. Phytotoxicity tests revealed no adverse effects on the vegetative and flowering flush of mango plants. Field trials showed that the 1.0% concentration of the ICW 50% formulation significantly reduced powdery mildew severity to 10.40%, with a disease reduction of 79.36% over the control. At 0.5% concentration, it recorded 11.20% disease severity and 77.77% disease reduction. Pre-harvest sprays of ICW 50% formulation at 1.0% and 0.5% concentrations resulted in post-harvest anthracnose incidence levels of 3.75% and 5.00%, with reductions of 88.46% and 84.61% over the control, respectively. Likewise, fruit dip treatments at 1.0% and 0.5% recorded 2.50% and 3.75% post-harvest anthracnose incidence, achieving 92.30% and 88.46% reduction over the control, respectively.