THE CICADA FAUNA AS PHYTOPLASMA VECTORS IN ISTRIAN VINEYARDS

The cicada fauna represents a considerable group of insects in vine-growing. Phytoplasma vine vectors insects are significant. They are fed from the phloem tissues of plants like cicadas from the families Cicadelidae, Coccidae, Fulgoridae and Psyilloidaea. Their phytoplasma is transmitted in a persistent way. Researches on cicada fauna, on the floristic structure of weeds and host plants of vine phytoplasma were done in 2005 and 2006 in Istrian vineyards. The research was being done in 10 vineyards on 11 localities. Cicade collecting was done with an entomological net by means of yellow sticky plates using an exhauster and a method of clonting. The collected cicadas were identified by means of binoculars and keys to identify species while the presence of phytoplasmas BN and Fd was defined by means of molecular analysis (PCR, RFLP). Listing and identifying the floristic structure of weeds were being cloned in the explored vineyards by means of keys to identify species. Samples of plant materials were taken for the analysis using PCR method by checking visually the typical symptoms caused by phytoplasma. Cicadas identifying and molecular analyses were being done at the Viticulture Institute for Research in Conegliano – Italy. During the researches, 243 insect samples were collected. Of the above mentioned number cicadas of 40 genus were identified in 207 samples. On the list of the floristic structure of Weeds 105 species of 36 families were identified. Corylus avellana L and Clematis vitalba L species were included in this list. These species showed sigus of phytoplasma disease and they were found near the explored vineyards. These two species were analysed on the presence for FD and BN phytoplasmas. The PCR method used in the molecular research on the presence of Fd and BN phytoplasmas was done on 34 insect samples and 22 plant samples. None of the mentioned sample was positive for FD and BN. The phytoplasma BN was found in the vine leaves of the Malvazia sort in the vineyards in Novigrad and Starići. The phytoplasma FD – type C was identified in the leaves sample of Clematis vitalba L in the Barat locality. The results of the researches conducted show that cicada species known as phytoplasma vine vectors are present in Istrian vineyards. The presence of these cicada species found in Istrian vineyards represent a potential danger for phytoplasma spreading, considering that the FD was found on the weed species of Clematis vitalba L.