Prevalence of Fungal Diseases on Mulberry Leaves in the Syrian Coast and Their Impact on the Productivity of the silkworm, Bombyx mori

Abstract

This study was conducted to investigate the prevalence of fungal diseases of mulberry leaves Morus spp. and its effect on the biological and productive characteristics of silkworms. Monthly field surveys were carried out in Latakia from mid-May to the end of September 2021. 40-60 mulberry trees were examined monthly, and symptoms observed on the affected leaves were recorded. Infection rate and severity were estimated. Samples were collected from infected leaves, and pathogenic fungi were isolated on artificial media, and causative agents were identified. Diseased leaves were collected to feed silkworms during the fourth and fifth larval instar. The average weight of the larvae, cocoon, and silk, and the effective rearing rate were calculated. The results showed the prevalence of 3 diseases on mulberry leaves in the study area: Phloeospora maculans leaf spot (recorded for the first time in Syria), anthracnose caused by Colletotrichum acutatum, and powdery mildew caused by Phyllactinia guttata. The highest infection rate and severity were recorded for Phloespora leaf spot (53.33 and 45.18%), followed by anthracnose (30 and 23%), and powdery mildew (30 and 28%), respectively, in September 2021. The results revealed that silkworms feeding on diseased leaves significantly reduced all production parameters, (larval mortality, ERR%, larval, cocoon, and shell weight) compared to the control. The reduction rate in the cocoon weight was 17.1, 12.1 and 21.8% for Phloespora leaf spot, anthracnose, and powdery mildew, respectively.

Keywords:

Bompex mori, mulberry, Phloespora leaf spot, anthracnose, powdery mildew.