Effect of Chitosan on Some Fungi Associated with Melon Stem Blight Disease in Basrah Governorate, Iraq

Abstract

This study was conducted during the period 2023-2024, and aimed to isolate and identify pathogens associated with melon stem blight disease, both morphologically and molecularly. Additionally, the research involved testing the pathogenicity of these pathogens and evaluating the in vitro effect of chitosan on them. The pathogenicity results showed that Macrophomina phaseolina and Fusarium equiseti were the most pathogenic in a pots experiment, and it was significantly superior to others in relation to seed germination rate, which reached 53.33 and 63.33%, respectively, and damping off, which reached 44.33 and 37.33%, respectively. The antagonistic ability of chitosan at concentrations of 2, 3, and 5% showed that the concentration of 5% completely inhibited all fungal species (100%), and the Rhizoctonia solani was the most affected fungus by chitosan as the inhibition rate reached 100.00%, when the two concentrations of 2 and 3% were used, whereas the fungus M. phaseolina was less affected by chitosan, and inhibition reached 55.66% at the 2% concentration.

Keywords:

Chitosan, melon, stem blight disease.