Journal of Chemical Ecology (1997) 23, 2455-2465

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Jörg Romeis, Thomas G. Shanower and Claus P.W. Zebitz (1997)
Volatile plant infochemicals mediate plant preference of Trichogramma chilonis
Journal of Chemical Ecology 23 (11), 2455-2465
Abstract: In India, eggs of the polyphagous noctuid moth Helicoverpa armigera on sorghum are parasitized to high levels by Trichogramma spp., but only rarely are parasitized eggs found on pigeonpea. This study was conducted to test whether volatile plant infochemicals contribute to the different parasitism levels observed on these two crops. In a four-armed airflow olfactometer, volatiles emitted by both sorghum and pigeonpea plants elicited a behavioral response form Trichogramma chilonis females. The parasitoids' response varied depending on the growth stage of the plant. Volatiles emitted by sorghum in the vegetative and reproductive stages arrested the parasitoids. T. chilonis females did not respond to volatiles from pigeonpea in the vegetative stage, but were repelled by volatiles from plants in the reproductive stage. Plants in the reproductive stage are preferred for oviposition by H. armigera. Thus, sorghum is attractive and pigeonpea repellent to T. chilonis females at the time when each plant is attractive to the host. This difference in the parasitoids' response may partly explain the different levels of egg parasitism reported from these two crops. The infochemicals involved in these plant-parasitoid interactions are discussed in the context of the current terminology.
(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): Jörg Romeis, Claus P.W. Zebitz

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

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Helicoverpa armigera Sorghum (crop) India
Helicoverpa armigera Pigeonpea (Cajanus cajan) India
Trichogramma chilonis (parasitoid) Helicoverpa armigera Sorghum (crop) India