Field demonstration of a semiochemical treatment that enhances Diorhabda carinulata biological control of Tamarix spp.

Authors: Gaffke, Alexander; SING, SHARLENE - Forest Service (FS); DUDLEY, TOM - University Of California; BEAN, DANIEL - Colorado Department Of Agriculture; RUSSAK, JUSTIN - University Of California; MAFRA-NETO, AGENOR - Isca Technologies, Inc; PETERSON, ROBERT - Montana State University; WEAVER, DAVID - Montana State University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2019
Publication Date: 9/10/2019
Citation: Gaffke, A.M., Sing, S.E., Dudley, T.L., Bean, D.W., Russak, J.A., Mafra-Neto, A., Peterson, R.K., Weaver, D.K. 2019. Field demonstration of a semiochemical treatment that enhances Diorhabda carinulata biological control of Tamarix spp.. Scientific Reports. 9(1):1-9. https://doi.org/10.1038/s41598-019-49459-5.
DOI: https://doi.org/10.1038/s41598-019-49459-5

Interpretive Summary: Tamarisk, also commonly called saltcedar, is a non-native weed invading waterways across the western United States. The northern tamarisk beetle, which is originally from Asia, was introduced to the United State to control the spread of saltcedar. The beetle can only feed on saltcedar and is excellent at controlling the plant. While many areas have achieved resounding success controlling tamarisk with the beetle, some infestations of the weed are enduring even with the increased pressure from the beetle. A USDA-ARS scientist with the Chemistry Research Unit in Gainesville, FL in collaboration with Montana State University, University of California, Colorado Department of Agriculture, U.S. Forest Service, and ISCA Technologies investigated the potential use of a pheromone to aggregate beetles and control these persistent tamarisk infestations. The field application of the pheromone was highly successful, allowing the researches to ‘herd’ the beetles to specific plants, resulting in major defoliation and dieback of the plants. The application of the pheromone can help the beetles control the invasive weed.

Technical Abstract: The northern tamarisk beetle Diorhabda carinulata (Desbrochers) was approved for release in the United States for classical biological control of a complex of invasive saltcedar species and their hybrids (Tamarix spp.). An aggregation pheromone used by D. carinulata to locate conspecifics is fundamental to colonization and reproductive success. A specialized matrix formulated for controlled release of this aggregation pheromone was developed as a lure to manipulate adult densities in the field. One application of the lure at onset of adult emergence for each generation provided long term attraction and retention of D. carinulata adults on treated Tamarix spp. plants. Treated plants exhibited greater levels of defoliation, dieback and canopy reduction. Application of a single, well-timed aggregation pheromone treatment per generation increased the efficacy of this classical weed biological control agent.