Study of Sudden Decline of Lavender in Bulgaria Caused by Candidatus Phytoplasma solani

Zhelyu Avramov

Abstract: The beneficial properties of medicinal and essential oil crops and medicinal and aromatic plants have been studied for thousands of years. Their cultivation corresponds to their growing demand, which leads to an annual increase in areas and an increase in the amount of herbal collection. In Bulgaria, the cultivation of some crops such as oil-bearing rose, lavender, and mint, has old traditions and world recognition and fame. Lavender as an intensive crop is often accompanied by the appearance of diseases and pests that can cause serious damage and in some cases even compromise the harvest. It is inadmissible in the production and its derivatives, the presence of even traces of the use of plant protection products. On the basis for the improvement of the applied methods of plant protection is an achievement of a good knowledge of the diseases in lavender plantations. An important point is the accurate, fast and reliable identification of pathogens in laboratory conditions of new and unknown phytoplasma diseases for Bulgaria. Examination of the lavender fields revealed symptoms of lavender disease with marked yellowing, reduction, straightening or sagging of the leaves, reduction and abortion of the inflorescences. A laboratory analysis total number on 91 lavender plant samples, 32 cicadas and 16 weed samples were performed. Phytoplasma infection in five samples from the Chirpan and Dobrich regions belonging to the Stolbur phytoplasma group, showing identical profiles was identified by PCR and RFLP analysis. For confirmation qPCR and sequencing was performed. The results are evidence that the established infection is of Sudden wilting of lavender caused by the phytoplasma ‘Candidatus Phytoplasma solani’ identified for the first time in Bulgaria.

Keywords: Bulgaria; Candidatus Phytoplasma solani; Lavender

Date published: 2022-02-25