Cylindrocarpon black foot in nurseries—two factors that can increase infection C. Probst & E. E. Jones & H. J. Ridgway & M. V. Jaspers Received: 17 May 2011 /Accepted: 21 October 2011 /Published online: 20 November 2011 # Australasian Plant Pathology Society Inc. 2011 Abstract Two common features of grapevine propagation were investigated to determine whether they increased incidence of black foot disease caused by Cylindrocarpon spp. Grapevine rootstock cuttings (varieties 101–14 and 3,309) were cold stored for 1, 2, 4 and 6 months, inoculated with three Cylindrocarpon spp. and grown on for 3 months prior to isolation. Results showed that increasing periods of cold storage increased the susceptibility of grapevine cuttings, with higher incidences of C. liriodendri (P= 0.041) and C. destructans (P=0.044), but not C. macro- didymum. Increasing duration of cold storage also increased disease severity by C. destructans (P=0.036), C. lirioden- dri (P=0.000) and C. macrodidymum (P=0.011). In the second experiment, rootstock cuttings (101–14) from source vines infected with Phaeomoniella chlamydospora were grafted to Sauvignon blanc and grown outdoors before inoculating them with the same three Cylindrocar- pon spp. The prior infection with P . chlamydospora caused significantly greater (P=0.047) incidence of C. liriodendri, but not C. destructans or C. macrodidymum. In all the above experiments, disease incidences and severities were greatest for C. liriodendri and least for C. destructans. These investigations demonstrated that grapevines cuttings and young vines subjected to two potentially stressful conditions were more susceptible to the black foot pathogens that are common in grapevine field nurseries worldwide. Keywords Cold storage . Phaeomoniella chlamydospora . C. liriodendri . C. destructans . C. macrodidymum Introduction The grapevine trunk pathogens that cause decline in newly planted grapevines in most wine-producing regions worldwide, include Phaeomoniella chlamydospora and Phaeoacremo- nium spp., which cause Petri disease, and Cylindrocarpon spp., which cause black foot disease (Oliveira et al. 2004), with plants frequently being affected by more than one disease (Armengol et al. 2001; Halleen et al. 2003). The symptoms of grapevine decline are stunting, late or retarded sprouting with shortened internodes on shoots, small chlorotic leaves, wilting and dieback (Oliveira et al. 2004). Petri disease is recognised by the presence of dark phenolics in xylem vessels of the trunks, which appear as raised, shiny dark dots in cross sections and streaks in longitudinal sections (Scheck et al. 1998; Mugnai et al. 1999). The sources of infection in young vines have been reported to include the infected propagation material, known as ‘cuttings’ produced by infected mother vines (Whiteman et al. 2007) and conidia produced from trunk crevices in these vines. The conidia are air-borne and so able to contaminate the propagation materials, including the cutting surfaces, hydration tanks, tools and wounds made during propagation (Larignon and Dubos 2000; Whiteman et al. 2003). Black foot is recognised by small necrotic lesions on roots and a dark purplish or reddish brown discoloration in the butts of affected vines; the necrosis eventually spreads across the whole trunk causing death of young vines (Rego et al. 2000; Halleen et al. 2006). However, when older vines are infected they demonstrate a more gradual decline, and it may take more than a year for infected vines to die (Scheck et al. 1998). The disease is soil-borne and so remains in the soil when an infected crop is removed; it was reported to be severe in Portugal in replanted vineyards C. Probst : E. E. Jones : H. J. Ridgway : M. V. Jaspers (*) Agriculture and Life Sciences Faculty, Lincoln University, PO Box 84, Lincoln, Canterbury, New Zealand e-mail: Marlene.Jaspers@lincoln.ac.nz Australasian Plant Pathol. (2012) 41:157–163 DOI 10.1007/s13313-011-0103-5