Agricultural and Forest Entomology (2011) 13, 423-433

Penelope Zanolli and Francesco Pavan (2011)
Autumnal emergence of Anagrus wasps, egg parasitoids of Empoasca vitis, from grapevine leaves and their migration towards brambles
Agricultural and Forest Entomology 13 (4), 423-433
Abstract: 1 The Anagrus `atomus ' parasitoid group (Hymenoptera: Mymaridae), associated with Empoasca vitis (Göthe) (Homoptera: Cicadellidae), overwinters on vegetation surrounding vineyards. The emergence of parasitoid adults from grapevine leaves in autumn was studied in north-eastern Italy, both in relation to the E. vitis egg-laying period and to the presence of leafhoppers overwintering as eggs on Rubus bushes.
2 Autumnal peaks of Anagrus captured using yellow sticky traps were observed first on grapevines and then on brambles. Parasitoid captures in vineyards were observed for more than 1 month after the last first-instar nymphs of the grape leafhoppers were noticed. Two species belonging to the A. `atomus ' group, Anagrus atomus and Anagrus ustulatus, were captured both on grapevines and brambles.
3 Parasitoids of the A. `atomus ' group can emerge from third-generation grape leafhopper eggs in accordance with two different development time patterns (i.e. normal or delayed). Individuals with delayed emergence required up to 2.2-fold more time to develop from an egg to adult than individuals with normal emergence. This meant that some parasitoid adults emerged in autumn from eggs of grape leafhopper laid in August.
4 A delayed emergence as a result of a slower development ensures that the A. `atomus ' parasitoid group is synchronized with the egg-laying of leafhoppers that overwinter as eggs on Rubus spp.
5 Consequently, leafhoppers overwintering as eggs on brambles play a key role in the ecology of the relationship between grape leafhoppers and the A. `atomus ' parasitoid group.
(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): Francesco Pavan

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
population dynamics/epizootiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Hebata vitis	Grapevine (Vitis)	Italy
Anagrus atomus (parasitoid)	Hebata vitis	Grapevine (Vitis)	Italy
Anagrus ustulatus (parasitoid)	Hebata vitis	Grapevine (Vitis)	Italy