Year: 2018
Type: article
Abstract: Italian vineyards are large-scale monocultures characterized by high pesticide pressure and removal of ecologically valuable structures. In the resulting highly disturbed and simplified systems, the insurgence of non-native species outbreaks can easier occur. In this framework, the preservation of semi-natural habitats and the adoption of more sustainable vineyard management practices are of particular importance in vineyard agro-ecosystems. In this thesis, the influence of vineyard management and landscape complexity on leafhopper species was investigated. Results shown that investigated factors can affect the leafhopper population densities and their natural control, and therefore they should be considered when pest control strategies are planned on a large scale. Moreover, some habitat manipulation practices, such as the management of spontaneous groundcover and the use of green manure, could be useful strategies to increase and/or enhance beneficial arthropods by providing fundamental sources for the survival and reproduction of natural enemies. The presence of non-mowed spontaneous grass in vineyards inter-rows favoured the abundance of natural enemies but also of grapevine leafhoppers, especially in organic. In particular, non-mowed vegetation could make harder the control of Scaphoideus titanus populations in organic vineyards, and its adoption should be carefully evaluated when the leafhopper occurs in the vineyards. Allowing the green manure to flowering for a prolonged period instead of mowing it early, as traditionally done by the growers, can favour a higher presence and abundance of beneficial arthropods while not influenced phytophagous densities. The timing of mowing must be accurate programmed to avoid the dispersal on leafhopper vectors. Investigations on the phenology of E. vulnerata suggest that the non-native pest can develop three generations per years in the new invaded area, and the presence of rural buildings and alternative hosts at vineyard margins favoured it overwintering and spreading into the vineyards. The impact of natural enemies on pest populations appeared to be limited to egg parasitism by Hymenoptera Mymaridae. A new approach aimed at promoting the impact of egg parasitoids and predators requires to be developed. In this context, the effectiveness of two generalist predators in controlling the leafhopper populations were tested both in laboratory and field conditions. Promising results obtained in laboratory trials suggested to release predators in vineyard, but their release did not give satisfactory results, except in only one trial in which the release of Orius majusculus significantly reduced the leafhopper numbers, suggesting to implement release techniques, densities and timing to improve the impact of anthocorids on grape leafhoppers. The design of modern viticultural systems should integrate management practices with lower environmental impact with ecological compensation measures to increase and enhance biodiversity in the vineyard agro-ecosystems. Habitat management practices can contribute to enhance biodiversity but in extremely simplified context, the only presence of temporary vegetation appears not enough to create a more pest-stable agro-ecosystem. Since the deployment of pesticides can favouring the insurgence of pest outbreaks and limited the successful implementation of biological control, more sustainable biological control strategies should be implemented to control pest population densities, such as for E. vulnerata in vineyards of North-eastern Italy.
Author: Giulia Zanettin
Language: English
Subfield: Insect Science
Domain: Life Sciences
SDGs: Life on land, Zero hunger
Open Access status: green
Awards: G4113645978, G6387244504
OpenAlex ID: W3012137248