The emerald ash borer (Agrilus planipennis) is a beetle native to Asia which was first identified near Detroit, Michigan and Ontario in 2002. It is now a serious invasive pest of North American ash trees in the genus Fraxinus. Emerald ash borer populations are spreading rapidly in the Midwest and Mid-Atlantic states of the USA, as well as adjacent regions of Ontario, Canada. “Within 25 years, practically no ash trees may remain on either side of the St. Lawrence Seaway”, said Akhlesh Lakhtakia, Charles Godfray Binder Professor of Engineering Science and Mechanics at Pennsylvania State University.
Emerald ash borer adult males locate females using visual cues, and males can be attracted by using dead male or female beetles pinned to host trees. The beetles are in the family Buprestidae, also known as Jewel Beetles as they often have metallic, iridescent colouring. Thomas Baker, Professor of Entomology at Pennslyvania State University and Michael Domingue have previously used dead female emerald ash borers for bait to trap the male beetles. The dead emerald ash borers are not ideal for trapping due to their fragility, therefore two researchers working in Lakhtakia’s laboratory have created a decoy beetle made from a mold of the female beetles body. The decoy has been coloured using a process of layering polymers with different refractive light properties to create the characteristic iridescent green colouring of the emerald ash borer. The team were able to find the right combination of polymers and number of layers in order to refract light and create a colour very similar to the beetle’s own colouring, creating a realistic visual decoy.
Adult emerald ash borers do not kill trees, it is the larvae that are the damaging stage, feeding internally on ash trees. Emerald ash borer infestations are difficult to detect during initial colonisation, since the larvae can take up to 2 years to develop and it can take some time for visible symptoms to occur in trees that are being attacked. Many current detection methods, such as girdled trees, require a significant amount of time and labour and are therefore not suitable for wide-scale detection. Early detection is critical to controlling the spread of the emerald ash borer.
The preliminary findings of pilot studies using decoy beetles to lure and trap males found that the decoys were 40% more effective than using dead female beetles to lure males. The findings of this work are due to be published in the April issue of the Journal of Bionic Engineering. The decoy beetles are relatively easy to mass produce, and have the potential to be a very useful detection and monitoring tool in the management of the invasive emerald ash borer beetle.
Drew P. Pulsifer, ,Akhlesh Lakhtakia,Jayant Kumar, Thomas C. Baker,, & Raul J. Martın-Palma (2012). Toward Pest Control Via Mass Production of Realistic Decoys of Insects Proceedings of SPIE, 8339 DOI: 10.1117/12.915924
Lelito, J., Fraser, I., Mastro, V., Tumlinson, J., Böröczky, K., & Baker, T. (2007). Visually Mediated ‘Paratrooper Copulations’ in the Mating Behavior of Agrilus planipennis (Coleoptera: Buprestidae), a Highly Destructive Invasive Pest of North American Ash Trees Journal of Insect Behavior, 20 (6), 537-552 DOI: 10.1007/s10905-007-9097-9
Lelito, J., Fraser, I., Mastro, V., Tumlinson, J., & Baker, T. (2008). Novel visual-cue-based sticky traps for monitoring of emerald ash borers,(Col., Buprestidae) Journal of Applied Entomology, 132 (8), 668-674 DOI: 10.1111/j.1439-0418.2008.01308.x