First molecular record of Thielaviopsis punctulata, the causative agent of black scorch blight disease on date palms in Iraq

Abstract

A laboratory study was conducted on samples of palm trees collected from Diyala Governorate, Iraq. The results of isolation and diagnosis of the samples that showed symptoms of black blight infection indicated that the fungus that causes the disease is Thielaviopsis punctulata. This is the first record of T. punctulata as a causative agent of black blight in Iraq. Moreover, the results of the microscopic examination showed that the fungus forms endoconidia from Phialidic conidiophores, and also produces aleoroconidia, thickened-walled chlamydial spores. In addition, the results of testing the pathogenic ability of the isolates on date palm seedlings showed that all the isolates of the pathogenic fungus showed the ability to cause the disease, but with different percentages compared to the percentage of the disease, where it was 0 in the comparison treatment that was free of pathogenic fungus, and isolate GP2 excelled, as it gave an infection severity of 100%, followed by the two isolates GP0 and GP1, which gave an infection severity of 93.33 and 80%, respectively.