Timely detection of a phytopathogen and its identification is an important step in the successful control of plant diseases. Wilt disease was found to cause mass mortality of plume plantlets obtained by clonal micropropagation and grown in the soil substrate. The aim of this study was identification of a phytopathogen that causes wilting of the plum plantlets (Prunus salicina Lindl.) obtained under in vitro conditions, at the stage of adaptation to non-sterile conditions. Microbiological analysis of stems and roots of the diseased plantlets revealed 23 isolates of fungi belonging to 4 genera. More than 60 % of the fungal isolates were identified as Gibellulopsis nigrescens (Pethybr.) Zare, W. Gams et Summerb. (basionym Verticillium nigrescens Pethybr.) according to the their cultural and morphological characteristics. Accompanying mycoflora included Acremonium spp., Cladosporium cladosporioides (Fresen.) G. A. de Vries, and Akanthomyces lecanii (Zimm.). It was concluded that G. nigrescens is the likely causal agent of wilt of the plum plantlets, although pathogenicity tests are needed to establish the virulence of G. nigrescens towards P. salicina.

Shumilova Lyudmila P., Kabotov Evgeniy E., Nekrasov Eduard V.

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