Synthetic Pheromone Helps Scientists Sniff Out Biocontrol Bug's Whereabouts

Saltcedar, the beetle's favorite food, is an invasive species from Eurasia that is established in more than 20 U.S. states, causing about $100 million annually in damages. The beetle, a natural enemy from China, has been cleared for release in several western states to biologically control the invasive tree. Current methods include herbicide spraying, burning and bulldozing, but none are considered long-term solutions to the problem, according to Robert Bartelt and Allard Cossé, entomologists with ARS' National Center for Agricultural Utilization Research at Peoria, Ill.

They synthesized the beetle's pheromone so that biological control practitioners, landowners, wildlife biologists and others could more easily determine how far the insects have moved from release sites, how quickly, and in what directions. Currently, beetle monitoring requires a sharp eye, dexterity with a sweep net, and a keen sense of direction while trekking through 12-foot-high thickets of saltcedar, notes Bartelt, at the ARS center's Crop Bioprotection Research Unit.

In studies there, the scientists and group colleague Richard Petroski synthesized the beetle's pheromone using affordable, off-the-shelf chemicals. Field tests in 2004 at a Lovelock, Nev., site showed the synthetic pheromone is attractive to both male and female beetles. In addition, 2004 field tests showed that odors from saltcedar foliage were very attractive to the beetles as well. Field tests in 2005 are planned to evaluate whether the pheromone and saltcedar odors work better when combined than when either is used alone.

Bartelt and Cossé's research is part of an ARS-led effort called the "Saltcedar Biological Control Consortium."