Alternative formulations of trap lures for operational detection, population monitoring, and outbreak forecasting of southern pine beetle in the United States
The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) is a
major destructive pest of Pinus L. In the southeastern United States, numbers of this species and a major
predator, Thanasimus dubius (Fabricius) (Coleoptera: Cleridae), captured during an annual springtime trapping
survey are used to make forecasts of the likelihood and severity of an outbreak during the following summer.
We investigated responses by both species to six lure formulations to evaluate their suitability for the survey
and allow integration of historical data sets produced with differing lure compositions. Trapping trials were
performed at four locations across three states (Louisiana, Mississippi, and Alabama) during spring, and at
these and one additional location (North Carolina) in fall 2016. All lures included the pheromone component
frontalin. Southern pine beetle preferred lures that additionally included the pheromone component endobrevicomin
and turpentine as a source of host odors (rather than a 7:3 mixture of monoterpenes alpha- and
beta-pinene). Thanasimus dubius displayed little discrimination among lure compositions. Lure preferences
by southern pine beetle did not differ significantly among locations in spring but were influenced by season.
Gas chromatography (GC)-electroantennographic detection analyses with southern pine beetle and GC-mass
spectrometry identified numerous known and potential semiochemicals that distinguished volatiles released
by the tested host odor devices. The lure combination that included endo-brevicomin and alpha/beta-pinene is
recommended for the trapping survey because of its high sensitivity for southern pine beetle and potential for
greater data integrity resulting from its reproducible composition.