Infestation potential of Dryocosmus kuriphilus Yasumatsu, 1951 (Hymenoptera: Cynipidae) in different natural populations of Castanea sativa Miller: an experimental ex situ test

Abstract

The Asian chestnut gall wasp was accidentally introduced in Italy in 2002 and spread across Europe in the following years, becoming a serious threat for chestnut cultivations and rural economies of many countries. Exploring the variation in susceptibility of the host genetic resources is crucial to face the spreading of this pest. We used an experimental approach for testing the differential susceptibility within and between populations of European chestnut. For doing this, we compared both the infestation level and the rate of immune individuals in trees from populations of Spain, Italy, and Greece. We found that the level of infestation is not significantly different in the different provenances but that a higher rate of immune trees occur in Greece. Our results suggest that two different contingents of trees compose Greek populations: one major group of trees with the same susceptibility as the other populations and a second minor group of trees resistant to gall wasp infestation. Our data lay the basis for improving the currently adopted measures to mitigate gall wasp impacts.

Keywords:

• Alien species
• invasive pest
• host immunity
• population differences
• null models
• chestnut gall wasp
• European chestnut

Acknowledgements

We wish to thank Michael Thompson for the improvement of the English style and three anonymous reviewers for their helpful comments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was made possible by the research grant award “VOCWASP” funded by IBAF-CNR.