Volatile Organic Compounds from the ClonePopulus x canadensis“Conti” Associated withMegaplatypus mutatusAttack

Megaplatypus mutatus(Chapuis) (Coleoptera, Platypodidae) is an ambrosia beetle native to South America. It builds internal galleries that weaken the tree trunks, causing them severe stem breakage and mortality in commercial poplar plantations. The host selection by maleM. mutatushas previously been correlated with the increasing diameter. This work explores the possibility that differential susceptibility of individual plants toM. mutatuscould be associated with volatiles emitted. The comparison of the VOCs profiles of attacked and nonattackedP.x canadensis“Conti” 12 duringM. mutatusflying season showed both qualitative and quantitative differences. The attacked plants, but not the nonattacked ones, showed the following compounds: a long chain aldehyde,α-ylangene,δ-cadinene,α-gurjunene, andβ-cubebene; on the other side,β-sesquiphellandrene andβ-chamigrene were detected only in nonattacked plants.α-Copaene is a common component of all the samples analyzed, but its proportion is increased in attacked individuals. Behavioral bioassays showed that males but not femalesM. mutatusare attracted toα-copaene. The relative increase ofα-copaene in attacked individuals and the positive behavioral answer of males to it suggest that this compound could play a role in the orientation of the pioneer male towards the most suitable host.

Effect of release rate and enantiomeric composition on response to pheromones of Megaplatypus mutatus (Chapuis) in poplar plantations of Argentina and Italy

Megaplatypus mutatus (=Platypus sulcatus Chapuis) is an Ambrosia beetle native to South America, which was recently introduced in Italy and its presence there is causing severe damage to the local poplar plantations. The male M. mutatus pheromone is composed of (S)-(+)-6-methyl-5-hepten-2-ol [(+)-sulcatol], 6-methyl-5-hepten-2-one (sulcatone) and 3-pentanol. A series of field trials testing dose, blend and enantiomer composition performed in Argentina and Italy evaluated attraction and found that the optimal release rate of pheromone components as baits in cross vane baited traps (CIPEIN-CV) was 6, 6 and 30 mg day−1 of sulcatone, (+)-sulcatol and 3-pentanol, respectively. It was also determined that racemic sulcatol is as effective as the pure (+)-isomer for the purpose of beetle catch, due to the inert nature of the (−)-isomer allowing the usage of low cost racemic sulcatol instead of highly expensive (+)-sulcatol. The results of our work contribute to the development of pheromone-based local technologies with low environmental impact and low cost for control or monitoring of an important pest.