History of phytoplasma diseases in Serbia

According to recent studies, presence of  Flavescence dorée (FD) in Serbia was confirmed only in Zupa Aleksandrovac and Nis (Duduk et al., 2004; Kuzmanović et al., 2004). Identification of new focal points in Niš, indicates possible wider dispersal of this disease in Serbia. Based on experience of countries dealing with epidemic of FD, presence of its vector is the main indicator of threatening epidemic. On all inspected localities in 2004 where  Scaphoideus titanus was registered, percent of infected plants ranged from 10 to 70%, while in region of Župa Aleksandrovac, up to 100%. On the other hand, using molecular method for detection, FD was so far detected only in regions of Zupa Aleksandrovac and Niš. It’s worth noting that extremely small number of localities in Serbia were analyzed using molecular method. However, increase of phytoplasmatic diseases of grapevine in Serbia is evident, irrelevant to their etiology. Spread of phytoplasmas is closely related to role of cicadas and psyllids in their transmission, thus, control of vectors represents one of the main measures in control and prevention of these diseases.

Symptoms of phytoplasmatic infection of grapevine are visible as partial color aberrations of leaves and necrosis between the main veins, and in later phase,  downward-rolled margins. These discolorations enlarge and form continuous yellow bands along the veins, which gradually extend over large parts of the leaf surface. The central portion of the discolored areas becomes necrotic and usually dries out. Color aberrations of leaves in infected plants vary between different cultivars. Red-fruited cultivars develop reddish discoloration of the leaves, while white-fruit cultivars show spectrum of yellow colors. Shorten internodes and atypical enbrachement of shoots are most often visible later during vegetation. These symptoms are easily recognizable and generally relaible sign of phytoplasma presence in vineyard.

FD on "red fruited" cultivar

          FD on "white fruited" cultivar

It's not possible to distinguish phytoplasmas, based only on symptoms on infected plants. In other words, it doesn't matter which phytoplasma causes the infection, since symptoms are more or less the same. Similar symtpoms are present on vines infected with leaf-roll virus (GLRaV), degenerative disease of grapevine transmitted by vectors and grafting. Analysis of samples on presence of leaf-roll virus gave positive results on several localitites in Serbia, what additionally makes the phytosanitary situation in vineyards more difficult. On several occassions, virus GLRaV-3 was detected in collected samples from localities in South Banat, Belgrade sorrounding and Velika Drenova.

Disease Bois Noir (Legno Nero) is caused by Stolbur phytoplasma (16SrXII-A). This phytoplasma is widely spread in Serbia and to date registered on several localities (Banat, Srem, Belgrade, Pomoravlje). Dispersal of this disease, which can obtain epidemic attributes, is in close relation with vectors and weeds status in vineyards. All mentioned diseases, Flavescence dorée (16SrV-C), Bois Noir (Stolbur 16SrXII-A) and grapevine leaf-roll disease (GLRaV), are present on EPPO A2 list.

 The only known vector of Flavescence dorée is  Scaphoideus titanus.  Vectors of Stolbur phytoplasma in vineyards are cicadas Hyalestes obsoletus and Reptalus panzeri (Palermo et al., 2004), but preliminary survey indicated possibility that some other cicadas are involved in transmission of  Stolbur phytoplasma as well. Vectors of leaf roll virus  GLRaV are coccids Planococcus ficus, Pseudococcus longispunus, P. affinis (Homoptera: Pseudococcidae) and Pulvinaria vitis (Homoptera: Coccidae).

Finally, it must be pointed out that phytoplasmas and diseases they cause are practically not studied yet in Serbia. Surveys conducted at the end of 2004, represent initial attempts to solve this problem.

Duduk B., S. Botti, M. Ivanović, B. Krstić, N. Dukić and A. Bertaccini (2004). Identification of Phytoplasmas Associated with Grapevine Yellows in Serbia. Journal of Phytopathology, 152: 575-579

Kuzmanović S, M. Martini, F. Ferrini, P. Ermacora, M. Starović, M. Tošić, R. Osler (2004). Stolbur i Flavescence doree fitoplazme prisutne na vinovoj lozi u Srbiji. V Kongres zaštite bilja Zlatibor, 2004. Zbornik rezimea, 138.

S. Palermo, M. Elekes, S. Botti, I. Ember, A. Alma, A. Orosz, A. Bertaccini and M. Kölber (2004). Presence of Stolbur phytoplasma in Cixiidae in Hungarian viticulture. Vitis 43 (4), in press.

Department of Plant Pests, Institute for Plant Protection and Environment Belgrade

Banatska 33, Zemun, tel/fax: 011 2611 762, E-mail: titanus_serbia@hotmail.com