Bactrocera oleae e batteri associati: prospettive per nuove strategie di controllo integrato del Tefritide

Studies carried out in the years 2007-2010 within the project "SIDIO" confirmed and highlighted that the olive fly Bactrocera oleae has two distinct types of relationship with bacteria: a close symbiosis with Candidatus Erwinia dacicola, and a temporary and occasionai association with Enterobacteriaceae and Pseudomonadaceae present on the olive phylloplane. Concerning Ca. Erwinia dacicola, some semi-field··trials allowed to verify how different products with bactericidal action, in particular copper sulphate and copper oxychloride, are able to cause until to 50% of mortality in eggs and larvae. Besides, these products showed a marked deterrent activity towards ovipositing females, evaluated, in terms of uninfested olives. The antibacterial activity of copper has been confirmed in laboratory bioassays using bacterial DNA extraction and amplification from the oesophageal bulb of flies watered with a mixtures based on copper oxychloride. Concerning the temporary associations which the olive fly has with bacterial epiphytic populations, a series of field trials revealed that a bacterial filtrate from cultures of Pseudomonas putida has a considerable attractiveness towards adults, especially against females. Again, the results show a significant practical importance for the development, after identification of active volatiles, of a new and more effective systems of monitoring and control of the pest.