Journal of Applied Entomology (2013) 137, 761-772

S.T. Moraglio, M. Corte and L. Tavella (2013)
Occurrence and impact of Agrilus spp. and associated egg parasitoids in hazel groves of Northwest Italy
Journal of Applied Entomology 137 (10), 761-772
Abstract: In several hazel (Corylus avellana L.) groves in the area of Langhe (Piedmont, Northwest Italy), many hazel branches suddenly withered, and in some cases, the whole tree died, with heavy economic losses for the farmers. Symptoms of jewel beetle attacks were detected on the trees. Eight Agrilus species were caught by traps from 2007 to 2009 in the surveyed hazel groves; among them, only four species have been known to develop on hazel. On the traps, Agrilus olivicolor Kiesenwetter was the most abundant species, while almost only Agrilus viridis (L.) was sampled by plant beating from 2008 to 2010. Moreover, almost all adults emerged from field-collected hazel wood belonged to this latter species that proved to be the main responsible for the severe attacks on the hazel trees. Agrilus viridis adults emerged from late May to late June, and generally lived until the end of August, while egg masses were observed from late May to late July. The egg parasitoid Oobius zahaikevitshi Trjapitzin was found in all of the investigated groves; adults emerged already from the first egg masses collected on hazel trees in late May-early June. O. zahaikevitshi was able to largely reduce A. viridis populations, with a parasitism rate of more than 50% in some groves. Recent attacks of A. viridis were related to a long period of drought; however, appropriate agronomic practices to minimize the effects of water stress and to conserve natural enemies, such as O. zahaikevitshi, could be more effective to protect hazel groves against boring beetle attacks.
(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): Luciana Tavella

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
general biology - morphology - evolution
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Agrilus olivicolor	Hazelnut (Corylus)	Italy
	Agrilus viridis	Hazelnut (Corylus)	Italy
Oobius zahaikevitshi (parasitoid)	Agrilus olivicolor	Hazelnut (Corylus)	Italy
Oobius zahaikevitshi (parasitoid)	Agrilus viridis	Hazelnut (Corylus)	Italy