Monitoring the effect of Oxalic Acid against tick population and non target arthropods in a meso-mediterranean environment

Hyalomma lusitanicum, the most abundant exophilic tick in Meso-mediterranean environments of Central Spain. Conventional control measures against this species of tick are difficult to apply in extensive open areas. It is especially difficult for ticks, such as H. lusitanicum, with a wide range of hosts, mainly rabbits for immature stages and large animals for adults. In a previous study the Oxalic Acid (OA), a bio-pesticide used in bee colonies for Varroa destructor control, demonstrated its efficacy against H. lusitanicum adults in lab conditions.The purpose of the present study was to evaluate the ixodicidal activity of different water dilutions of OA in natural field conditions. A 0.15% water solution of a commercial acaricide product containing Fenitrotion 25% and Cipermetrine 2.5%, and a control just with water, were used to compare results. 400 l of each product was irrigated in 5 plots of 50 x 30 m (1500m2) in Latin Squares, with 10 m of passage non treated between them. Previously to the treatments, tick abundance record on passage vegetation was determined. Immediately after irrigation pitfall traps were placed in each plot and 24 hours later tick abundance record and soil samples for Berlesse technique were taken in each square. As expected, tick reduction 24 hours after OA treatment was not as high as the observed after conventional treatment (81%). Tick reduction after OA treatment was 59% (OA 0.5% and OA 3%) and 77% (OA 1%). No differences between OA treated and control plots were observed in relation with the arthropods fauna by Berlesse and only a small reduction was detected by pitfall in OA 0.5%. The arthropods fauna of conventional treatment was significantly reduced. These preliminary results are the first evidence of the applicability of OA to the sustainable management of tick population in Meso-mediterranean conditions