Entomologia Experimentalis et Applicata (2012) 144, 93-100

Anna Lehrman, Mikaela Torp, Johan A. Stenberg, Riitta Julkunen-Tiitto and Christer Björkman (2012)
Estimating direct resistance in willows against a major insect pest, Phratora vulgatissima, by comparing life history traits
Entomologia Experimentalis et Applicata 144 (1), 93-100
Abstract: Many Salix species (Salicaceae) have a high energy quotum and efficient nitrogen use, resulting in a high and stable biomass production, making these plants suitable as bioenergy crops. However, Salix coppices are sensitive to herbivory by chrysomelid beetles, such as Phratora vulgatissima L. (Coleoptera: Chrysomelidae), and to maintain high biomass yields over several years, durable plant resistance is necessary. We have developed a reliable and efficient bioassay that can be used as a tool for detection of resistance against P. vulgatissima in Salix. Screening of six clones of one susceptible (Salix viminalis L.) and one resistant (Salix dasyclados Wimm.) willow species, by the response of several life history traits of larval and adult P. vulgatissima, identified egg production as the most reliable trait for resistance. We show that a 2-week bioassay of oviposition rate is sufficient for a trustworthy estimation of both total egg production and survival of adult leaf beetles. In addition, to elucidate the variation in resistance among the studied clones, leaf concentrations of various phenolic compounds were compared with the key life history traits of the beetles. Phenolic compounds, especially salicylates, have previously been reported as the main factor controlling Salix resistance against P. vulgatissima. Indeed we found higher levels of salicylates in the resistant clones and larval performance was negatively correlated to the concentration of salicylates in the leaves. In addition, we found indications of negative effects of a luteolin derivative and quercetin-3-glucoside on leaf beetle performance, but further studies are needed to elucidate the specific roles that the different phenolic compounds play in plant resistance.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Johan A. Stenberg, Christer Björkman

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phratora vulgatissima	Willow (Salix)