Dendrolimus pini can be a serious defoliator of pine trees in some European countries. The monitoring of this insect is important, but no single standardized capture technique exists for monitoring purposes. 2 A range of insect trap types (delta sticky, G-trap, Unitrap and cross-vane Unitrap), colours (green, red and white delta traps and yellow and green cross-vane Unitraps) and types of capture liquid (glycol and salt solutions) were tested to determine the most effective trap for D. pini monitoring. Trap colour (yellow and green) was also tested for beneficial Hymenoptera and Diptera. 3 The Unitraps and cross-vane Unitraps were the most effective trap types, but the latter trap that contained glycol solution was less effective than a dry trap. 4 Trap colour did not have any effect on the catches of D. pini, but yellow Unitraps captured more Diptera (Phoridae and Tachinidae) and Hymenoptera (Pteromalidae, Ceraphronidae and Braconidae) than green traps. In contrast, the egg parasitoid Telenomus tetratomus preferred green traps. Overall catches of beneficial insects were relatively low, except Phoridae. 5 The Unitraps are recommended for the efficient monitoring of D. pini unless other factors such as trap cost or remote monitoring locations justify the use of other traps.

Black pheromone-baited traps are commonly used for monitoring Monochamus galloprovincialis, a vector of Bursaphelenchus xylophilus, although few studies have been conducted on its response to color (black, white, and clear). The objective of our studies was to evaluate the attractiveness of different colors to M. galloprovincialis and non-target species: Spondylis buprestoides and predatory Thanasimus formicarius and T. femoralis. Laboratory tests of fifteen colors against immature and mature M. galloprovincialis revealed some differences in their color preference. In two field tests, eight colors of coroplast vanes in cross-vane traps were compared with unpainted white (a reference (RF)). The first test confirmed the laboratory results, i.e., RF was slightly more attractive to M. galloprovincialis than pastel yellow, reseda green, and cyan blue, but trap color had no significant effect on any of the insect species studied. In the second test, the attractiveness of RF was highest and significantly different from pure white (for all four species), light blue, and pine green (except S. buprestoides). Overall, the unpainted white traps appeared to be most effective in catching M. galloprovincialis. Thanasimus spp. responded to the colors similarly to M. galloprovincialis; therefore, either trap design or lure composition should be modified to reduce their catches.

With the increasing threat to forests in Europe from the invasive pine wood nematode (PWN) Bursaphelenchus xylophilus, effective methods are needed to monitor and reduce populations of its insect vector, the pine sawyer beetle Monochamus galloprovincialis. In the present study, we tested the effectiveness of different trap types (multiple-funnel, cross-vane, and triangular), colours (black, white and clear), and lubricant (polytetrafluoroethylene, PTFE) treatments (different PTFE formulations and timing of trap treatment) on the catches of M. galloprovincialis and three most commonly captured non-target beetle species (the xylophagous Spondylis buprestoides and two predators, Thanasimus formicarius and T. femoralis) in Poland. Of the traps not treated with PTFE, the white and black 6-funnel traps were most effective in trapping M. galloprovincialis beetles, while the catches in the cross-vane traps (both white and clear) were low. Trap treatment with PTFE significantly increased trap effectiveness, regardless of PTFE type and time of application. The catches of S. buprestoides were affected by trap type, while those of T. formicarius depended on trap colour and size. Both species seem to respond positively to ethanol and/or α-pinene in the lure composition. PTFE treatment had a significant effect on the catches of T. femoralis. In conclusion, for the monitoring of M. galloprovincialis, we recommend the white cross-vane traps treated with dry PTFE. They are less but still effective in catching the target species, while their use, together with lures containing no ethanol and α-pinene, greatly reduces the catches of non-target insects S. buprestoides and T. formicarius.