Responses of Phradis parasitoids to volatiles of lavender, Lavendula angustifolia—a possible repellent for their host, Meligethes aeneus
Hymenopterous parasitoids of herbivorous insects can be useful biocontrol agents in integrated pest management strategies. However, the potential effects on these beneficials of new components in such strategies are often neglected. Essential oil of lavender, Lavendula angustifolia (Miller) (Lamiaceae), has recently been identified as a potential repellent in new control strategies being developed for the pollen beetle Meligethes aeneus (Fabricius) (Coleoptera: Nitidulidae), a major pest of oilseed rape, Brassica napus L. (Brassicaceae). We tested the electrophysiological and behavioural responses of two common parasitoids of M. aeneus: Phradis interstitialis (Thomson) and P. morionellus (Holmgren) (both Ichneumonidae) using coupled gas chromatography-electroantennodetection (GC-EAD) and olfactometry techniques. Both species elicited electrophysiological responses to lavender oil volatiles, including two compounds known to be repellent to M. aeneus. However, the parasitoids gave no significant responses to the odours of lavender oil in behavioural bioassays and there was no evidence to suggest that lavender-treated oilseed rape plants would reduce host habitat location by parasitoids of the target pest.
KeywordsBrassica napus Electroantennography Meligethes aeneus Non-host plant volatiles Olfactometer Phradis interstitialis Phradis morionellus Pollen beetle
We thank Barry Pye for spraying the plants and Ingrid Williams for her support throughout this study. This work was facilitated by John Pickett and funded by the UK Department for Environment, Food and Rural Affairs. Rothamsted Research receives grant-aided support from the UK Biotechnology and Biological Sciences Research Council.
- Bernays EA, Chapman RF (1994) Host-plant selection by phytophagous insects. Chapman & Hall, New YorkGoogle Scholar
- Bjostad LB (1998) Electrophysiological methods. In: Millar JG, Haynes KF (eds), Methods in chemical ecology. Kluwer Academic Publishing, Dordrecht, The Netherlands. pp 339–375Google Scholar
- Ekbom B, Kuusk AK, (2001) Pollen beetles (Meligethes aeneus) and resistance against pyrethroids. Vaxtskyddsnotiser 65:39–42Google Scholar
- Evans KA, Allen-Williams LJ (1994) Laboratory and field response of the pollen beetle, Meligethes aeneus, to the odour of oilseed rape. Physiol Entomol 19:285–290Google Scholar
- Horstmann K (1971) Revision der europäichen Tersilochinen I (Hym., Ichneumonidae). Veröffentlichungen der Zoologischen Staatssammlung (München) 15:13–45Google Scholar
- Landolt PJ, Hofstetter RW, Biddick LL (1999) Plant essential oils as arrestants and repellents for neonate larvae of the codling moth (Lepidoptera : Tortricidae). Environ Entomol 28:954–960Google Scholar
- Mauchline AL (2003) Behavioural and chemical ecology of Meligethes aeneus: effects of non-host plant volatiles. Ph.D. Thesis, The Open University. pp 197Google Scholar
- Nilsson C (2003) Parasitoids of pollen beetles. In: DV Alford (eds) Biocontrol of oilseed rape pests. Blackwell Publishing, Oxford, UK. pp 73–86Google Scholar
- Vet LEM, Lewis WJ, Carde RT (1995) Parasitoids foraging and learning. In: RT Carde WJ Bell (eds) Chemical Ecology of Insects. Chapman & Hall, New York. pp 65–104Google Scholar
- Wegorek P (2006) Resistance of pollen beetle (Meligethes aeneus F.) to pyrethroids, chloronicotinyls and organophosphorous insecticides in Poland. IOBC/wprs Bull 9(7):137–142Google Scholar