- Host Symptoms
- Caption:
- Prunus tree affected by ESFY (left) showing early defoliation and decline compared to an unaffected tree (right) (For permission to reproduce images email b.schneider@bba.de).
- Source:
- Dr B. Schneider, BBA
Albania, Austria, Belgium, Bosnia and Herzegovina, Czech Republic, Germany, Greece, Hungary, Italy, Romania, Serbia & Montenegro, Slovenia , Spain, Switzerland, Turkey, England.
Symptoms:
Ca. P. prunorum is associated with European stone fruit yellows (ESFY) disease, which includes diseases of apricot, cherry, peach and Japanese plum (Lorenz et al., 1994; Seemüller and Foster 1995; Marcone et al., 1996). ESFY affected trees flower and shoot in winter, which leads to lack of fruit production and chlorosis of the leaves later in the growing season. The early break in dormancy increases the susceptibility of affected trees to frost, which can cause damage to the phloem. During the early stage of disease often only a few branches are affected but the whole tree may become affected as the disease progresses. Infected shoots are typically shorter and bear smaller, deformed leaves. Leaves can drop prematurely. Shoots may die back. Yield is reduced. Fruit on affected branches develops poorly and may fall prematurely. Many stone fruit tree species or varieties show decline (Nemeth, 1986; Seemüller and Foster 1995).
Specific symptoms in apricot (apricot chlorotic leafroll) include upward curling of leaves, which are chlorotic. In Japanese plum (plum leptonencrosis) the leaf margins roll upward and leaves may be chlorotic. In peach the midribs and lateral veins of the leaves can become enlarged and corky tissue develops along the veins. The leaves become red and roll upward. In cherry the first symptom observed is slight chlorosis of leaves in summer. Flowers are malformed and fruit set is poor in the following year. Rosetting of leaves occurs on affected shoots and young shoots remain unlignified. (Nemeth, 1986; Seemüller and Foster 1995)
The pathogen:
Phytoplasmas are obligate intracellular parasites, principally restricted to the phloem cells of infected plant hosts or the salivary glands of their insect vectors (McCoy, 1984). Phytoplasmas have not been successfully cultured in vitro (Kirkpatrick, 1991). Ca. P. prunorum is transmitted by the psyllid Cacopsylla pruni (Carraro et al., 1998b, 2001) or through planting material. Ca. P. prunorum can be detected using a PCR based on the 16S rRNA gene with universal primers for all known phytoplasmas and identified by RFLP analysis or sequencing (Seemüller et al., 1998a).
Hackberry Celtis australis
Ash Fraxinus excelsio
Dog rose
Wild cherry P. avium
Almond Prunus dulcis
Apricot Prunus armeniaca
Black cherry Prunus mahaleb
Blackthorn Prunus spinosa
Cherry (myrobalan) plum Prunus cerasifera
Japanese plum Prunus salicina
European plum Prunus domestica
Japanese (flowering) cherry Prunus serrulata
Peach Prunus persica
Carraro L, Osler R, Loi N, Ermacora P, Refatti E. 1998. Transmission of European stone fruit yellows phytoplasma by Cacopsylla pruni. Journal of Plant Pathology 80, 233-239.
Jarausch W, Danet JL, Labonne G, Dosba F, Broquaire JM, Saillard C, Garnier M. 2001. Mapping the spread of apricot chlorotic leaf roll (ACLR) in southern
Jarausch W, Jarausch-Wehrheim B, Danet JL, Broquaire JM, Dosba F, Saillard C, Garnier M. 2001. Detection and identification of European stone fruit yellows and other phytoplasmas in wild plants in the surroundings of apricot chlorotic leaf roll-affected orchards in southern
Jarausch W, Lansac M, Dosba F. 1999. Seasonal colonization pattern of European stone fruit yellows phytoplasmas in different Prunus species detected by specific PCR. Journal of Phytopathology 147, 47-54.
Lorenz KH, Dosba F, Poggi Pollini C, Llacer G, Seemüller E. 1994. Phytoplasma diseases of Prunus species in
McCoy RE. 1984. Mycoplasma-like organisms of Plants and invertebrates. In: Krieg NR and Holt JG (eds). Bergey’s manual of systematic bacteriology volume 1 pp792 – 793,. William and Wilkins, Baltimore/London.
Marcone C, Ragazzino A, Seemüller E. 1996. European stone fruit yellows phytoplasma as the cause of peach vein enlargement and other decline diseases of stone fruits in southern
Nemeth M. 1986. Virus, Mycoplasma and Rickettsia Diseases of Fruit Trees, Martinus Nijhoff Publishers,
Seemüller E, Foster JA, 1995. European stone fruit yellows. In: Ogawa JM, Zehr EI, Bird GW, Ritchie DF, Uriu K, Uyemoto JK, eds. Compendium of stone fruit diseases.
Seemüller E, Schneider B. 2004. Taxonomic description of ‘Candidatus Phytoplasma
Seemüller E, Marcone E, Lauer U, Ragozzino A, Göschl M, 1998. Current status of molecular classifiation of the phytoplasmas. Journal of Plant Pathology 80, 3-26.
