Constitutive and herbivore-induced volatiles in pear, alder and hawthorn trees
Scutareanu, P. ; Bruin, J. de; Posthumus, M.A. ; Drukker, B. - \ 2003
Chemoecology 13 (2003). - ISSN 0937-7409 - p. 63 - 74.
induced plant volatiles - anthocorid predators - natural enemies - identification - host - semiochemicals - populations - kairomones - responses - defense
Qualitative and quantitative differences among pear cultivars were found in constitutive and Cacopsylla-induced volatiles, depending on experimental treatment of the trees (i.e., uninfested and partly or completely infested by psyllids). Blend differences were also found between pear cultivars and wild-type pear, alder and hawthorn-the latter trees are frequently present in pear orchard hedgerows. Interesting differences were found in the presence of methyl salicylate and (E,E)-alpha-farnesene, two compounds previously found to mediate attraction of predatory bugs towards psyllid-infested pear trees. Methyl salicylate is expressed constitutively and is induced systemically by infestation in the whole plant of all four cultivars. (E,E)-alpha-farnesene on the other hand showed also systemic induction in Bartlett, NY10355 and Beurre Hardy, but in partially infested Conference trees it was induced locally, only in herbivore-damaged leaves. No methyl salicylate or (E,E)-alpha-farnesene were identified in honeydew. In field collected headspace samples of alder leaves infested by aphids and leaf beetles we found methyl salicylate but no (E,E)-alpha-farnesene, whereas in uninfested hawthorn neither were identified. Insight in the variability of damage-related pear volatiles will have important implications for integrated pest management in the field.
|Pear tree responses to psyllid infestation: intercultivar variation in emission of volatiles
Scutareanu, P. ; Bruin, J. ; Drukker, B. ; Posthumus, M.A. ; Sabelis, M.W. - \ 2001
IOBC/WPRS Bulletin 24 (2001)5. - ISSN 0253-1100 - p. 221 - 226.
Volatiles from Psylla-infested pear trees and their possible involvement in attraction of anthocorid predators
Scutareanu, P. ; Drukker, B. ; Bruin, J. ; Posthumus, M.A. ; Sabelis, M.W. - \ 1997
Journal of Chemical Ecology 23 (1997)10. - ISSN 0098-0331 - p. 2241 - 2260.
Previous work showed that anthocorid predators aggregate around gauze cages containing Psylla-infested trees in a pear orchard. Because anthocorids responded to odor from Psylla-infested leaves in a laboratory test, it was hypothesized that these aggregative responses in the field were triggered by olfaction of compounds associated with Psylla injury. We present chemical analyses of volatiles from damaged and undamaged plants and studies on behavioral responses of anthocorid predators to compounds released by damaged plants. Leaf headspace volatiles from clean and Psylla-infested pear trees were collected on Tenax and identified by GC-MS after thermodesorption. Twelve volatiles were found exclusively in headspace samples from Psylla-infested leaves. Six were present in significantly higher quantities in samples from infested leaves: the monoterpene, (E,E)-?-farnesene, the phenolic, methyl salicylate, and the green leaf compounds, (Z)-3-hexen-1-yl acetate, (Z)-3-hexen-1-ol, 1-hexyl-acetate, and 1-penten-3-ol. These compounds are known to be produced by plants, and damage by pear psyllids seems to trigger their emission. Blend composition varied and was partly correlated with tree or leaf age and degree of Psylla infestation. To study whether compounds associated with leaf injury elicit olfactory responses in anthocorid predators, apple-extracted (E,E)-?-farnesene, synthetic methyl salicylate, and (Z)-3-hexen-1-yl acetate were offered in a Y-tube olfactometer to field-collected adult Anthocoris spp. Significant positive responses were found to both the monoterpene and the phenolic, but not to the green leaf volatile. The results lend support to the hypothesis that predator attraction to herbivore-infested pear trees is mediated by herbivory-induced plant volatiles.
|A trap for monitoring pear psylla predators using dispensers with the synomone methylsalicylate.
Molleman, F. ; Drukker, B. ; Blommers, L. - \ 1997
In: Unknown / Sommeijer, M.J., Francke, P.J., - p. 177 - 182.
|Leaf volatiles and polyphenols in pear trees infested by Psylla pyricola evidence of simultaneously induced responses
Scutareanu, P. ; Drukker, B. ; Bruin, J. ; Posthumus, M.A. ; Sabelis, M.W. - \ 1996
Chemoecology 7 (1996). - ISSN 0937-7409 - p. 34 - 38.
|Field studies on the European Earwig (Forficula auricularia L.) as predator of the woolly apple aphid (Eriosoma lanigerum Hausm.).
Stap, J.S. ; Mueller, T.F. ; Drukker, B. ; Blom, J. van der; Mols, P.J.M. ; Blommers, L.H.M. - \ 1987
Mededelingen - Universiteit Gent, Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen 52 (1987)2a. - ISSN 1373-7503 - p. 423 - 431.
|The possible significance of various groups of predators in preventing pear Psylla outbreaks
Blom, J. van der; Drukker, B. ; Blommers, L. - \ 1985
Mededelingen - Universiteit Gent, Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen 50 (1985)2a. - ISSN 1373-7503 - p. 419 - 424.