In December 2026, characteristic symptoms of a dangerous disease – bacterial canker, or oleander knot disease – were recorded on Nerium oleander L. plants in the greenhouses of the Donetsk Botanical Garden. The plants had been imported through the Autonomous Nonprofit Organization «Congress and Exhibition Bureau of the City of Moscow». This disease had not been previously recorded in the Donetsk Botanical Garden subtropical plant collection. Phytosanitary surveys of oleanders growing on the southern coast of Crimea (vicinity of Yalta), conducted by the authors in 2024, also revealed the presence of this disease. Symptoms include tumor-like tissue overgrowths and deformities of leaves, inflorescences, and fruits, resulting in reduced ornamental value and disrupted flowering. The record of the disease on imported plant material emphasizes the need for quarantine measures for plants entering botanical garden collections.

Bondarenko-Borisova I.V., Gubin A.I.