Identification of phytopathogenic fungi causing leaf spot and leaf dry rot on Aloe vera grown in Ninh Thuan province

Abstract

Leaf spot and leaf dry rot are two common diseases of Aloe vera grown in Ninh Thuan, greatly affecting the quality and yield of harvested leaves. In this study, based on morphological and molecular analysis methods, two fungi were identified as pathogens for Aloe vera, including: Alternaria alternata causing leaf spot disease and Curvularia hawaiiensis causing leaf dry rot. The rDNA region containing ITS sequence of the fungus isolated from the leaf spot and leaf dry rot samples was more than 99% similar to ITS sequence of A. alternata and C. hawaiiensis, respectively. Simultaneously, pathogenicity tests showed that healthy Aloe vera plants, when infected with these two fungi, produced typical symptoms of leaf spot and leaf dry rot on leaves. The results of re-isolation of disease samples from pathogenicity tests obtained fungi with morphological characteristics similar to the original isolates. These results are the basis for further studies about the infection mechanism as well as prevention methods for Aloe vera diseases.