Hyalesthes obsoletus in Serbia and its role in the epidemiology of corn reddening.

Surveys were carried out in order to verify and monitor the presence of Hyalesthes obsoletus Signoret (Homoptera Cixiidae) populations in Serbia under different environmental conditions. H obsoletus was present in all the localities investigated and different population dynamics were observed in relationship to the host plant. The development cycle of the vector and population density collected on Convolvulus arvensis L. was earlier and lower than those on the population collected on Urtica dioica L. In Udovice region, both nymphs and adults were observed on Artemisia vulgaris L. Since many larvae were found on the root apparatus of A. vulgaris, H obsoletus appears to be adapted to the species and able to reproduce as well. Moreover, transmission trials were carried out with H obsoletus population collected on nettle near corn field, allow verifying the ability of the cixiid to transmit the corn reddening disease. Amplification of phytoplasma DNA was obtained after nested PCR assays from corn samples tested after 40 days from insect caging and from batches of H obsoletus collected on nettle from the same population used for cage-transmission. RFLP analyses allow identification of the detected phytoplasmas as "stolbur" in both, corn experimentally infected and H obsoletus specimens tested.