Optimization of traps for live trapping of Pine Wood Nematode vector Monochamus galloprovincialis

Abstract

The pine sawyer beetle Monochamus galloprovincialis, a secondary pest of pines in Europe and North Africa, has become important as it was identified as the vector in Europe of Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD). An effective trapping system is needed, not only for monitoring the insect vector but also for direct control of its population. Trapping may also provide key information on the nematode load carried by the beetles, allowing early detection of infections, provided that captured beetles remain alive within the trap. Highly effective attractants have been developed in recent years that are commonly used in combination with diverse standard trap designs. In this study, several trap designs were developed and compared to commercial standard models in order to determine which designs maximized the number of attracted insects actually caught and the proportion of them remaining alive. In total, 12 trap designs were evaluated in five field experiments carried out in France, Spain and Portugal. Teflon coating applied to the whole trap and extended, ventilated collecting cups resulted in a significant improvement of trap performance. These modifications led to significant increases of pine sawyer catches, up to 275%, when applied to multiple‐funnel or black cross‐vane traps, compared to standard designs. Furthermore, a significant proportion of the captured beetles remained alive within the trap. These findings have been used to develop new commercial traps (Econex Multifunnel‐12® and Crosstrap®; Econex, Murcia, Spain) available to forest managers. A model for insect survival within the trap was also fitted. Elapsed time between consecutive samplings, mean relative humidity and maximum radiation were the three most significant variables. Thus, traps should provide a suitable sample of live insects if sun exposure of the trap is minimized and a reasonable sampling schedule is implemented.

Attractants for management of the pine sawyer beetle Monochamus sutor, a potential vector of Bursaphelenchus xylophilus

“…Improved traps (Álvarez et al. ) baited with a blend of pine sawyer pheromone, bark beetle and host kairomones are currently being used to manage pine wood nematode in the three locations where pine wilt disease is under eradication in Spain.…”

“…In recent years, significant progress has been made in understanding the chemical ecology of European Monochamus species such as M. galloprovincialis (Ibeas 2007, Pajares et al 2004, 2010, resulting in highly attractive lures with practical applications in PWD management ( Alvarez-Baz et al 2015a). Improved traps ( Alvarez et al 2014) baited with a blend of pine sawyer pheromone, bark beetle and host kairomones are currently being used to manage pine wood nematode in the three locations where pine wilt disease is under eradication in Spain.…”

How do sex and sexual maturation influence the response of Monochamus galloprovincialis to host odours?

“…By contrast, it has been shown that male beetles may become aggressive to each other in confined environments (Álvarez et al. ). However, generally, the number of positive responses to host odours did not differ between mature and immature beetles.…”

“…), and recent field studies showed that black pheromone traps were more effective, suggesting positive interactions between visual and chemical cues (Álvarez et al. ). Much fewer studies addressed the question of host finding cues in reproductively immature Monochamus beetles.…”

Susceptibility of larvae and adults ofMonochamus galloprovincialisto entomopathogenic fungi under controlled conditions

“…This is done with the implementation of strict sanitary measures in affected forests, by locating, felling and removing/destroying symptomatic trees (which contain insect larvae and nematodes in the wood) during the winter months, to prevent adult emergences infected by PWN (Sousa et al 2011). During spring and summer, M. galloprovincialis adults are exhaustively controlled by the use of baited traps, which effectively diminish beetles populations (Alvarez et al 2014;Bonif acio et al 2012). Such techniques to control larvae and adults are intended to partially prevent new pine wilt disease focus.…”