Behaviour of Putative Lemon Rootstocks towards Phoma tracheiphila Root Infections
Citrus mal secco, a tracheomycosis caused by the fungus Phoma tracheiphila (Petri) Kanc, et Ghik. , is the most serious disease of lemon (Citrus limon Burm.)in the central and eastern areas of the Mediterranean basin and on the east cost of the Black Sea. In root infections occurring on young plants, the pathogen may remain compartmentalized as latent infection in the inner xylem, leading to the particular form of the disease known as mal nero , which is characterized by blackish discoloration of the hard wood and by the absence of any external symptom. Eventually, after several years, the pathogen reaches the sapwood, causing a sudden collapse of the canopy. Since sour orange (C. aurantium L.), the most common rootstock of lemon, is susceptible to the disease, the search for rootstocks tolerant to mal secco deserves attention. Field investigations were undertaken over two decades to evaluate the behaviour of several putative lemon rootstocks, either ungrafted or grafted with Femminello lemon, towards P. tracheiphila root infections. The rootstocks tested included; C. taiwanica (Tan. and Shim) C. R. C. 2588; Yuzu orange (C. junios Sieb. ex Tan) ; sour orange S. Marina II selection; Ichang lemon C. R. C. 1215 and Siamelo C. R. C. 2586. Six years old plants, both grafted and ungrafted, were inoculated on two opposite roots, about 5 cm in diameter. After twelve years from the inoculation, the surviving plants were counted and cut at the base. The trunk of both grafted and ungrafted plants was sectioned and the percentage of the blackish discoloured area was determined. The tested rootstocks, singularly or as group behaved differently towards mal secco root infections. In particular, besides the general lowering of resistance induced by the lemon scion, the results pointed out appreciable tolerance for S. Marina II selection of sour orange and Siamelo.
Mal nero Mal secco disease Citrus Latent infection
F. Nigro I. Pentimone A. Ippolito M. G. Salerno
Department of Plant Protection and Applied Microbiology, University of Bari, Via G. Amendola 165/A, 70126,Ban, Italy
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
1153-1156
2008-10-01（万方平台首次上网日期，不代表论文的发表时间）