- Pest Management: biological control, integrated pest management
Air potato, Dioscorea bulbifera, is an invasive vine introduced to North America from Asia and Africa. In the introduced range, it is able to grow rapidly, out competing native vegetation and can smother vast swaths of native habitat. Mechanical and chemical control of air potato can be time consuming, cost-prohibitive, and can also damage native plant populations. Due to limitations of these conventional control measures, a biocontrol program was initiated. This resulted in the approval and release of the air potato beetle, Lilioceris cheni, in 2012. Lilioceris cheni has proven to be effective at controlling air potato in many areas; however, enhanced biocontrol is needed where environmental conditions limit the effectiveness of the agent, or where only transient levels of defoliation are observed. Lilioceris cheni has been observed to aggregate in the field, suggesting plant produced volatiles could be used to aggregate populations to target locations. These targeted aggregations could result in increased impacts to air potato. Therefore, we investigated sources of attractants for L. cheni. Preliminary trials indicate L. cheni demonstrates positive chemotaxis towards plants previously damaged by conspecifics suggesting that herbivore induced host plant volatiles could be used as attractants to air potato beetles. Further understanding of the role of semiochemicals in aggregating populations of L. cheni could lead to novel management strategies to enhance the air potato biocontrol program. We propose to identify the volatiles involved in L. cheni aggregation and assess the efficacy of attractive lure in field situation to increase biological control of D. bulbifera.
Project objectives from proposal:
- Determine response of Lilioceris cheni to Dioscorea bulbifera (undamaged, mechanical, larval, and adult).
Insect behavioral bioassays will be conducted to determine what types of damaged plants are most attractive to adult L. cheni. A fully crossed research design will be utilized to determine the hierarchy of response of the adults to the different damage treatment (i.e. what type of damage is most attractive).
- Identification of chemicals governing cheni attraction to D. bulbifera.
Leaf volatiles from the most attractive treatment identified in the previous objective will be collected utilizing a volatile collection system and identified using gas-chromatography coupled with mass spectrometry (GC-MS). After compound identification, an attractive blend for L. cheni will be formulated into field lures.
- Validation of lures and field trial of bulbifera semiochemical attractants.
Lures developed in Objective 2 will be validated for attraction utilizing standard two-choice insect behavioral bioassays. Once lure attraction has been determined, field trials will take place in areas infested with air potato and with L. cheni present. Effectiveness of the lures will be determined through adult capture rates in field.