Effectiveness of mass trapping in the reduction of Monochamus galloprovincialis Olivier (Col.: Cerambycidae) populations

Abstract

Monochamus galloprovincialis Olivier beetles vector the causal agent of pine wilt disease (PWD), nematode Bursaphelenchus xylophilus (Steiner and Bührer) Nickle, in Europe. Traps and attractants have been optimized for the capture of M. galloprovincialis, increasing the possibility of developing methods of lowering its population in PWD-affected areas with the aim of either eradicating the disease or containing the spread of it. To evaluate the effectiveness of such mass-trapping campaigns, two sets of experiments were carried out in 2010 and 2013. The release of 353 laboratory-reared beetles in the experimental area of 2010 facilitated the evaluation of capture–mark–recapture (CMR) procedures in the calculation of population abundance estimates using the POPAN formulation of the Jolly–Seber model, a prerequisite for the assessment of mass trapping. Abundance estimates derived from best-fitting parameters fell within one standard error of the real figures, proving the method appropriate. In 2013, four trap densities were tested in six 36 ha plots. To evaluate the removed proportions, the local beetle population was estimated in a contiguous 260 ha study area. A superpopulation of 21 319 individuals could be calculated from the CMR data, corresponding to a rough density of 82 individuals per hectare. Evaluated trapping densities removed 4.66%, 20.50%, 33.33% and 59.80% of M. galloprovincialis population at 0.02, 0.11, 0.25 and 0.44 traps/ha, respectively, thus the estimated 95% removal would occur at 0.82 traps/ha. These results suggest that substantial reduction of M. galloprovincialis abundances might be achieved via mass trapping and that this represents a very promising management method for the containment or eventual eradication of B. xylophilus at the areas affected by the PWD.