Anatomical changes in the stems of highbush blueberry (Vaccinium australe Small), caused by the fungus Godronia cassandrae f. vaccinii (Peck) Groves

Abstract

Some histological changes were observed in blueberry stems infected by the fungus G.cassandrae. Dead cells of subepidermal collenchyma and cortical parenchyma filled with brown flocculent deposits were seen in the lesion areas. Pycnidia characteristic for the conidial stage of the fungus (Topospora myrtilli) were found in the collenchyma layer. The diseased tissues were found to be separated from the healthy ones by a layer of cork cells which was initiated under the epidermis and ended under the pericycle. Beneath this cork layer lamellar collenchyma and collenchyma-like phelloderma formed. Similar histopathological changes were observed in blueberry stems infected by seven other fungi.