Fusarium oxysporum f. sp. asparagi is one of the main problems associated with the roots of asparagus plants and inflicting serious losses worldwide. A novel and eco-friendly strategy to reduce pathogen resistance and management of the Fusarium crown and root rot is using chitosan and Trichoderma harzianum as a sustainable treatment approach to improve both disease resistance and yields, while also effectively managing the asparagus product. In this study, the effect of chitosan and Trichoderma harzianum on growth promotion and control of Fusarium crown and root rot in asparagus plants was investigated. diseased plants from the main production areas of Iran were surveyed. The in vitro antifungal properties of chitosan solutions (concentrations of 5, 10, 15 and 20 mg/mL) and T. harzianum strain were evaluated by the dual culture method. T. harzianum and chitosan solution (20 mg/mL) gave the largest inhibition zone against F. oxysporum and were selected for further studies in the greenhouse. Chitosan (20 mg/mL) and T. harzianum were applied as seed treatments and they significantly reduced disease incidence by 92% and 73% respectively, compared to the control.
