First Report of Occurrence of Verticillium Wilt on Some Ornamental Trees in Sicily

In July 1998, a widespread lethal collapse of butterfly tree (Bauhinia purpurea L.), puka tree (Meryta sinclairii Hook.), Indian laurel (Ficus microcarpa L.), golden rain tree (Koelreuteria paniculata Laxm.), and Brazilian pepper tree (Schinus terebinthifolius Raddi.) has been observed in an ornamental growing area near Catania in eastern Sicily. The diseased plants showed yellowing of the leaves and twig dieback. In cross sections of infected trunks, roots, twigs or shoots, characteristic discoloration of xylem vessels was observed, resembling a vascular wilt disease. The disease was chronic with a lingering decline progressing for years. The isolate that was consistently recovered from diseased tissues on PDA was identified as Verticillium dahliae Kleb., based on verticillate conidiophores with phialides and conidia and melanized microsclerotia. Pathogenicity tests were performed on 4- to 6-month-old seedlings of all five ornamental plants by inoculating a suspension of the fungus (1). Symptoms were observed after 5 to 7 months, and V. dahliae was reisolated, confirming Koch's postulates. To our knowledge this is the first report of V. dahliae on Indian laurel, golden rain tree, and Brazilian pepper tree in Italy, and the first report of the disease on butterfly tree and puka tree. Reference: H. A. Melouk and C. E. Horner. Phytopathology 65:767, 1975.