Novel Bioassay Demonstrates Attraction of the White Potato Cyst Nematode Globodera Pallida (Stone) to Non-volatile and Volatile Host Plant Cues Kevin Farnier & Marie Bengtsson & Paul G. Becher & Johanna Witzell & Peter Witzgall & Sanja Manduríc Received: 18 October 2011 / Revised: 20 January 2012 / Accepted: 31 January 2012 / Published online: 14 April 2012 # Springer Science+Business Media, LLC 2012 Abstract Potato cyst nematodes (PCNs) are a major pest of solanaceous crops such as potatoes, tomatoes, and eggplants and have been widely studied over the last 30 years, with the majority of earlier studies focusing on the identification of natural hatching factors. As a novel approach, we focused instead on chemicals involved in nematode orientation to- wards its host plant. A new dual choice sand bioassay was designed to study nematode responses to potato root exu- dates (PRE). This bioassay, conducted together with a tra- ditional hatching bioassay, showed that biologically active compounds that induce both hatching and attraction of PCNs can be collected by water extraction of incised potato roots. Furthermore, our results demonstrated that PCN also were attracted by potato root volatiles. Further work is needed to fully understand how PCNs use host plant chem- ical cues to orientate towards hosts. Nevertheless, the simple attraction assay used in this study provides an important tool for the identification of host-emitted attractants. Keywords Chemical attraction . Bioassay . Plant-parasitic nematode . Plant-nematode interaction . Root volatiles . Root exudate Introduction The potato cyst nematodes (PCNs) Globodera pallida and G. rostochiensis are among the most important pests of solana- ceous plants. Infestation by PCNs occurs immediately after hatching when second stage juveniles (J2s) invade host plants roots where they retard their development. Retardation of root extension reduces water and nutrient uptake by the plant and decreases the yield of potatoes (Trudgill et al., 1998). In Europe, a 9 % loss in total potato yield is attributed to PCNs (Evans and Rowe, 1998). Crop rotation leading to slow de- pletion of nematode populations as well as breeding of resis- tant varieties are the most frequently employed strategies since the prohibition of nematicides in many European countries (Chitwood, 2003). Recent investigations have focused on new control strategies based on the use of bacteria that directly or indirectly affect the performance and survival of plant- parasitic nematodes (Tian et al., 2007). In the last 20 years, effort has been directed to the isolation and identification of host-derived PCN egg hatch- ing factors (Twomey, 1995; Perry and Gaur, 1996; Devine and Jones, 2000a, b; Ryan et al., 2000; Devine et al., 2001; Ryan and Jones, 2003, 2004; Ryan and Devine, 2005). The identified hatching agent from potato roots, solanoeclepin A (Schenk et al., 1999), has a complex polycyclic structure and has yet to be artificially synthesized (Hue et al., 2005). Consequently, commercial production of this compound is not likely in the near future. Thus, there is a need to develop other environmentally and economically sustainable strate- gies for the control of PCNs. K. Farnier : M. Bengtsson : P. G. Becher : P. Witzgall : S. Manduríc Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden J. Witzell Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden S. Manduríc Jordbruksverket, Växtskyddscentralen, PO Box 12, SE-230 53 Alnarp, Sweden K. Farnier (*) Department of Zoology, La Trobe University, Melbourne, VIC 3086, Australia e-mail: kfarnier@students.latrobe.edu.au J Chem Ecol (2012) 38:795–801 DOI 10.1007/s10886-012-0105-y