Journal of Chemical Ecology (2004) 30, 945-964

Stefano Colazza, J. Steven McElfresh and Jocelyn G. Millar (2004)
Identification of volatile synomones, induced by Nezara viridula feeding and oviposition on bean spp., that attract the egg parasitoid Trissolcus basalis
Journal of Chemical Ecology 30 (5), 945-964
Abstract: Bean plants (Vicia faba L. and Phaseolus vulgaris L.) damaged by feeding activity of Nezara viridula (L.) (Heteroptera: Pentatomidae), and onto which an egg mass had been laid, produced volatiles that attracted the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae). Extracts of volatiles of broad bean and French bean plants induced by adults of N. viridula as a result of their feeding activity, oviposition activity, and feeding and oviposition activity combined were analyzed by gas chromatography-mass spectrometry (GC-MS), and tested in Y-tube olfactometer bioassays as attractants for T. basalis females. In extracts from undamaged leguminous plants, green-leaf volatiles were absent or scarcely detected, and monoterpenes and sesquiterpenes were present at trace levels. No significant differences were detected in the profiles of volatiles of undamaged plants, and undamaged plants on which bugs were allowed only to lay eggs. In contrast, feeding and oviposition by adults of N. viridula induced in both leguminous plants a significant increase in terpenoids such as linalool, (E)-ß-caryophyllene, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, and (3E)-4,8-dimethyl-1,3,7-nonatriene, which was induced only in French bean plants. Quantitative comparisons revealed increased levels of (E)-ß-caryophyllene in extracts from feeding-damaged plants with N. viridula egg masses compared to feeding-damaged plants without egg masses. In Y-tube olfactometer bioassays, T. basalis females were attracted by extracts of both leguminous plants only when N. viridula adults were allowed to feed and oviposit upon them. Fractionation of extracts of volatiles from broad bean plants with N. viridula feeding damage and egg masses yielded two fractions, but only the fraction containing (E)-ß-caryophyllene was attractive to the egg parasitoid. These findings indicate that N. viridula feeding and oviposition induce leguminous plants to produce blends of volatiles that are characterized by increased amounts of (E)-ß-caryophyllene, and these blends attract female T. basalis. The role of (E)-ß-caryophyllene as a potential synomone for T. basalis is discussed.
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Link to article at publishers website
Database assignments for author(s): Stefano Colazza, Jocelyn G. Millar

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
environment - cropping system/rotation
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Nezara viridula
Trissolcus basalis (parasitoid)	Nezara viridula	Beans (Phaseolus)
Trissolcus basalis (parasitoid)	Nezara viridula	Cowpea and relatives (Vigna)