Petri Disease
Petri disease is caused by several fungi which affect vines 1-10 years old (Del Río Conesa and et al., 2002; Fourie and Halleen, 2002) . Decline of young vines has been found in vineyards worldwide (Ferreira et al., 1994; Mugnai et al., 1999; Pascoe and Cottral, 2000) . External symptoms include stunted growth, shortened internodes, interveinal chlorosis, leaf necrosis, decline and possibly dieback (Fourie and Halleen, 2002; Scheck et al., 1998).
Petri (1912) described the internal symptoms of this disease as dark brown or black streaks in the vascular tissue, as well as tyloses and gums in the xylem. When the vine is cut in cross section the streaking can be seen as dark spots close to the pith or in the annual growth rings. The host is likely predisposed to the pathogenic phase of this fungus by stress (Ferreira et al., 1994) . Pathogenicity studies have shown that P. chlamydospora as well as P. aleophilum and P. inflatipes are able to induce a decline in young grapevines (Scheck et al., 1998) . Phaeomoniella chlamydospora is consistently isolated in the rootstock of vines showing symptoms of Petri grapevine decline (Morton, 1999; Mugnai et al., 1999) .
Leslie Long
References:
•Del Río Conesa, J.A. and et al.,., 2002. Study of Petri Disease in Grapevine. Proposal of a Possible Solution. Nutri-Fitos. 77 - 84.
•Ferreira, J.H.S., Wyk, P.S., and Venter, E., 1994. Slow dieback of grapevine: association of Phialophora parasitica with slow dieback of grapevines. South African Journal of Enology and Viticulture 15:9 - 11.
•Fourie, P.H. and Halleen, F., 2002. Investigation on the occurrence of Phaeomoniella chlamydospora in canes of rootstock mother vines. Australasian Plant Pathology 31:425 - 426.
•Morton, L., 1999. Viticulture and grapevine declines: lessons of black goo. Phytopathologia Mediterranea 39:59 - 67.
•Mugnai, L., Graniti, A., and Surico, G., 1999. Esca (Black Measles) and Brown Wood Streaking: Two Old and Elusive Diseases of Grapevines. Plant Disease 83:404 - 417.
•Pascoe, I. and Cottral, E., 2000. Developments in grapevine trunk diseases research in Australia. Phytopathologia Mediterranea 39:68 - 75.
•Petri, L., 1912. Observations on grapevine wood alterations following wounding. Le Stazioni Sperimentali Agraria Italiane 45:501 - 547.
•Scheck, H., Vasquez, S., Fogle, D. and Gubler, W.D., 1998. Grape growers report losses to black-foot and grapevine decline. California Agriculture 52: 19- 23.
