MYCOPLASMA-LIKE ORGANISMS IN DIFFERENT STRAWBERRY VARIETIES IN THE EMILIA-ROMAGNA REGION, ITALY.
A lethal disease on tree strawberry varieties, Fern, Douglas and Parker was first found in the Emilia-Romagna, region of Italy in the fall 1986 and winter 1987. The disease caused reddening of the leaves, stunting, crown proliferation and loss of plant vigor. Several leaf- hoppers Empoasca solani (Curtis) and Emelyanoviana mollicula (Boheman) were found and collected during our surveys in and near the infected fields. In some fields where strawberry plants did not show symptoms, clover plants (Trifolium repens) showing stunting and witches'broom symptoms were food. Infected strawberry leaves grafted into Vinca rosea plants, showed within two-three months symptoms typical of mycoplasma-like organism infection. Samples of petioles and leaves from the three infected strawberry varieties, grafted Vinca- rosea and clover were fixed, sectioned, stained and examined under Jeol T8 and Zeiss' electron microscopes. Mycoplasma-like organisms (1LO8) were found at low concentration in phloem and sieve tubes of strawberry and clover plants but were absent in Vinca rosea tissue. In view of our failure to demonstrate the presence of MLOs also in Vinca rosea plants, further researchers on the nature, cause and natural spread of this disease are needed.
Pisi, A. and Vicchi, V. (1989). MYCOPLASMA-LIKE ORGANISMS IN DIFFERENT STRAWBERRY VARIETIES IN THE EMILIA-ROMAGNA REGION, ITALY.. Acta Hortic. 265, 615-618