Annals of Applied Biology (2019) 175, 302-312

Abdelhameed Moussa, Nicola Mori, Monica Faccincani, Francesco Pavan, Piero Attilio Bianco and Fabio Quaglino (2019)
Vitex agnus-castus cannot be used as trap plant for the vector Hyalesthes obsoletus to prevent infections by ' Candidatus Phytoplasma solani' in northern Italian vineyards: Experimental evidence
Annals of Applied Biology 175 (3), 302-312
Abstract: Bois noir (BN), the most prevalent disease of the grapevine yellows complex, causes considerable yield loss in vineyards. BN is associated with phytoplasma strains of the species ' Candidatus Phytoplasma solani' (taxonomic subgroup 16SrXII-A). In Europe, the BN phytoplasma is transmitted to grapevine mainly by Hyalesthes obsoletus, a polyphagous cixiid completing its life cycle on stinging nettle and field bindweed. As a result of the complexity of BN epidemiology, no effective control strategies have been developed. In previous studies conducted in the eastern Mediterranean coast of Israel, chaste tree (Vitex agnus-castus) was found to be the preferred host plant of H. obsoletus but did not harbour BN phytoplasma. Thus, a 'push and pull' strategy was suggested based on the fact that chaste tree plants located at vineyard borders was an effective trap plant for H. obsoletus adults. However, in other studies carried out in the eastern Adriatic coast of Montenegro, chaste tree was found to be a key source plant for BN phytoplasma transmission to grapevine. This study aimed to investigate (i) the interaction between chaste tree and H. obsoletus through survival, attractiveness and oviposition experiments conducted comparing the behaviour of H. obsoletus in chaste tree versus stinging nettle and grapevine and (ii) the capability of chaste tree to harbor ' Ca. P. solani' in northern Italy through transmission trials. H. obsoletus adults were found to survive on chaste tree and grapevine over a 1 week period and prefer chaste tree to grapevine. Moreover, H. obsoletus produced eggs and overwintered as nymphs on chaste tree, even if at a lesser extent than on stinging nettle. H. obsoletus originating from nettle was found able to transmit ' Ca. P. solani' to chaste tree (2 plants of 16 were found infected by the BN phytoplasma strain St5 identified in H. obsoletus specimens). These results increased our knowledge about the role of Vitex agnus-castus as host plant of H. obsoletus and BN phytoplasma in northern Italy and do not recommend considering chaste tree as trap plant at vineyard borders.
(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): Nicola Mori, Francesco Pavan, Piero Attilio Bianco

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
transmission/dispersal of plant diseases

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phytoplasma solani	Grapevine (Vitis)	Italy
	Hyalesthes obsoletus	Grapevine (Vitis)	Italy