Control of Hyalesthes obsoletus Signoret, vector of Bois Noir, using entomopathogenic agents: preliminary results.

Control of Hyalesthes obsoletus, vector of Bois Noir, using entomopathogenic agents: preliminary resultsN. Reggiani1, N. Mori2 , L. Maistrello11 University of Modena and Reggio Emilia, Department of Agricultural& Food Sciences, via G.Amendola 2, Pad. Besta, 42100 Reggio Emilia, Italy2 University of Padova, DAAPV - Entomology, v.le dell\u2019Universit\ue0 16, 35020 Legnaro (PD), ItalyEmail: lara.maistrello@unimore.itThe planthopper Hyalesthes obsoletus Signoret (Homoptera, Cixidae) is vector of the grapevine yellow Bois Noir, one of the most important phytoplasmosis in Europe. Reduction of phytoplasma associated diseases incidence relies on the control of the insect vectors and on the eradication of affected host plants. Management of Bois Noir is especially difficult because 1) both the vector and the phytoplasma can develop also in plants other than grapevines and 2) the overwintering younger instars of the insect live underground feeding on the roots of wild plants normally nearby vineyards (like nettle and bindweed) and chemical treatments are ineffective and unsustainable (Mori et al., 2008). The aim of this work was to evaluate the possibility to control the young forms of the leafhopper by means of entomopathogenic agents applied to nettle roots (AAVV, 1997; Vanesa Toledo et al., 2007, Reggiani and Maistrello, 2010). A first semi-field test was performed on young leafhoppers obtained from hundreds of wild H. obsoletus adults that had been captured and allowed to breed in a greenhouse with nettle pots during the previous summer. In late spring, pots containing groups of these juveniles were treated by sprinkling the ground with selected strains of entomopathogenic fungi (Beauveria bassiana and Paecilomyces lilacinus) and nematodes (Heterorhabditis bacteriophora and Steinernema feltiae). The mortality of H. obsoletus was recorded on day 7, 14, and 21 after the treatment. A second trial was made in field conditions selecting plots (3 m2 surface) in proximity of vineyards with a high quantity of nettle. These plots were sprayed on the middle of July at the ground level with the same enthopathogenic agents strains used for the first test. The plots were isolated with proper cages and the number of emerged adults was monitored during the whole flight period using yellow sticky traps. The obtained results show a good activity of the tested biopesticides, in particular for B. bassiana in the semi-field trial, and for nematodes in the field trials. The experiments suggest that microbiological control of the planthopper vector could represent a promising option for the integrated management of Bois Noir. Key words: Bois noir, entomopathogenic agents, Hyalesthes obsoletus, microbiological control, biopesticidesReferencesAAVV -1997- Manual of Techniques in Insect Pathology. Academic Press Inc. San Diego, California - USA. Edited by Lawrence Lacey, 409 pp.Mori N., Pavan F., Bondavalli R., Reggiani N., Paltrinieri S., Bertaccini A., -2008-. \u201cFactors affecting the spread of \u201cBois Noir\u201d disease in north Italy vineyards\u201d. Vitis: 47 (1), 2008: 65-72Reggiani N., Maistrello L. -2010- \u201cAn approach to the control of Hyalesthes obsoletus, vector of Bois Noir, using entomopathogenic agents \u201d. In: Proceedings of IX European congress of entomology, Budapest (HU) 22-27 August 2010, 143-144Vanesa Toledo A., Marino de Remes Lenicov A.M., L\uf2pez Lastra C.C. -2007- \u201cPathogenicity of fungal isolates (Ascomycota: Hypocreales) against Peregrinus maidis, Delphacodes kuscheli (Hemiptera: Delphacidae), and Dalbulus maidis (Hemiptera: Cicadellidae), vectors of corn diseases.\u201d Mycopathologia 2007 163:225-23