El-Hoseny, MEEl-Fallal A, AmiraEl-Sayed, AKDiab, ASadik, AS2020-02-062020-02-0620101812-1837https://cutt.ly/irAXfqrMSA Google ScholarSquash is considered as one of the most important crops in Egypt and worldwide. Zucchini yellow mosaic potyvirus (ZYMV) is considered as one of the most important viruses infects squash. We used the biological, serological and cytopathological studies to identify an Egyptian isolate of ZYMV. Results showed that the Egyptian isolate of ZYMV showed systemic symptoms in the form of severe mosaic and vein banding on Cucurbita pepo cv. Eskandarani under open field conditions. Direct antigen coated (DAC)-enzyme-linked immunosorbent assay (ELISA) using polyclonal antibodies was used as a diagnostic tool for detecting ZYMV in the virus-infected C. pepo samples. It showed positive reactions with ZYMV antiserum. Filamentous virus-like particles measuring 750X13 nm was successfully purified from ZYMV-infected squash plants, based on the use of polyethylene glycol and ultracentrifugation. The electron microscope of ultrathin sections of virus-infected leaf tissues revealed the presence of cylindrical inclusions as pinwheels, laminated aggregates and scrolls in the cytoplasm of cells infected with ZYMV. In addition, disorganization of plastids, nucleus and mitochondria in the virus-cells infected was also observed. In addition, the nucleotide of CI gene of the viral isolate under investigation was determined and its similarities to some overseas isolates were addressedenUniversity for Electron microscopyVirusIsolateArticle