Responses of Conophthorus spp. (Coleoptera: Scolytidae) to behavioral chemicals in field trials:: A transcontinental perspective

We tested six behavioral chemicals, pityol, conophthorin, 4-allylanisole, verbenone, 2-hexenol, and alpha -pinene, in a series of field trials directed at six combinations of Conophthorus Hopkins - Pinus L. spp. (Pinaceae) in sites distributed across North America. Beetle - host tree combinations included Conophthorus ponderosae Hopkins on Pinus ponderosa Laws., C. ponderosae on Pinus monticola Dougl., Conophthorus conicolens Wood on Pinus pseudostrobus Lindl., Conophthorus teocotum Wood on Pinus teocote Schl. & Cham., Conophthorus coniperda (Schwarz) on Pinus strobus L., and Conophthorus resinosae Hopkins on Pinus resinosa Ait. trans-Verbenol was tested only on C. resinosae on P. resinosa. Traps baited with pityol caught more beetles than unbaited traps in nearly all of the assays, and conophthorin consistently inhibited male beetle response to pityol for all species tested. Behavioral responses of species of Conophthorus to alpha -pinene appeared to parallel host phylogeny, inasmuch as beetles using Haploxylon pines as hosts utilized alpha -pinene as a synergist for the beetle-produced pityol, whereas beetles using Diploxylon pines as hosts did not. alpha -Pinene was a synergist for pityol in C. ponderosae on P. monticola and C. coniperda on P. strobus, but not for species of Conophthorus on any other pines tested. Conophthorus ponderosae on P. ponderosa was the only beetle-host combination tested where verbenone was a synergist fur pityol, but tills effect was not consistent in all years of testing. It was also the only beetle-host combination in which 4-allylanisole was a repellent. For all other beetle-host combinations, verbenone was neutral to slightly repellent and 4-allylanisole was either synergistic or neutral in pityol-baited traps. Promising synergists and interruptants/repellents were identified for implementation in pest-management regimes, including conophthorin as an interruptant for all species of Conophthorus tested, 4-allylanisole as an interruptant for C. ponderosae on P. ponderosa, cr-pinene as a synergist for pityol in all species tested on Haploxylon pines, and 4-allylanisole as a synergist for pityol in C. conicolens and C. coniperda.