Journal of Pest Science (2023) 96, 683-693

Christine Becker, Katharina Herrmann and Annette Reineke (2023)
Biological control in a changing climate: plant-mediated impact of elevated CO₂ concentration on Lobesia botrana eggs and egg parasitism by Trichogramma cacoeciae
Journal of Pest Science 96 (2), 683-693
Abstract: Climate change can affect biological pest control by altering trophic interactions. Elevated carbon dioxide (CO₂) concentrations can reduce host plant quality and, in turn, alter herbivore and natural enemy preference and performance. Using the Geisenheim VineyardFACE (free-air carbon dioxide enrichment) facility, we studied plant- and herbivore-mediated bottom-up effects of elevated CO₂ concentration on the European grapevine moth, Lobesia botrana, and the parasitoid Trichogramma cacoeciae. Grapevine inflorescences of two cultivars cultivated at ambient or elevated CO₂ (aCO₂ and eCO₂: 400 and 480 ppm) in the VineyardFACE were incorporated into L. botrana artificial diet. Eggs laid by the respective adults were parasitized by T. cacoeciae. Egg size and emergence rate of L. botrana as well as parasitism rate, parasitoid emergence rate and egg size preference of T. cacoeciae were evaluated. We observed an indirect grapevine cultivar-dependent bottom-up effect of CO₂ on both herbivore and egg parasitoid. Compared to aCO₂, eCO₂ resulted in larger host eggs and higher parasitism rates regarding Riesling-feeding but not regarding Cabernet Sauvignon-feeding L. botrana larvae. Parasitoid emergence rate was higher when L. botrana had fed on Riesling compared to Cabernet Sauvignon-diet. Egg size preference depended on the host's diet: T. cacoeciae preferred larger L. botrana eggs when the larvae had fed on grapevine-containing diet but not when they fed on standard artificial diet. Our results highlight the importance of the host's diet for the parasitoid's preference and performance. They furthermore suggest that the future efficiency of L. botrana-biocontrol by T. cacoeciae will not decrease under elevated CO₂ concentrations.
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Database assignments for author(s): Annette Reineke

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
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.
	Lobesia botrana	Grapevine (Vitis)	Germany
Trichogramma cacaeciae (parasitoid)	Lobesia botrana	Grapevine (Vitis)	Germany