ACTING on aphid behaviour to reduce virus yellows transmission to sugar beets. – AGIR

Context and objectives :
The ban of neonicotinoids as seed treatments to manage aphids transmitting sugar beet yellows viruses constitutes a major challenge for farmers and sugar beet industries. Previous studies (ex : PNRI, Modefy) have shown that sugar beet varieties and certain companion plants can influence the behaviour of Myzus persicae, considered as the main vector of yellows viruses. Some sugar beet varieties alter the feeding behaviour of the aphid, and are less favourable to its establishment. Some companion plants can also reduce aphid populations on sugar beets through mechanisms that are not yet well identified. The main objective of this project is to combine these two levers, to identify strategies that would limit both the attractiveness of beets and the acquisition of viruses by aphids. At the beginning, the project is at a TRL 4 because previous experiments on varieties, sustaining the very encouraging preliminary results, have been done under controlled conditions. The identification of promising sugar beet varieties and companion plants will be pursued under controlled conditions, and the best combinations will be tested in experimental plots (years 1 and 2), and in the field (years 3). At the end, the project will reach a minimum of TRL 6.

Method :
Sugar beet varieties selection will be carried out with high-throughput video-phenotyping, electro-penetrography, and virus transmission tests. The selection of combinations of varieties and companion plants will be carried out though aphid choice tests and trials in experimental plots. The selected combinations will then be deployed at the field-scale to evaluate their global interest. The identification of Volatile Organic Compounds (VOC) and non-volatile metabolites that have an effect on aphid behaviour will allow to explore new solutions.

End users :
The final users are sugar beet farmers, and the transfer of knowledge could be done by the French Technical Institute for Sugar beet (ITB) (articles, trial visits…). The output of this project could also be useful for other sectors.

Relevance and durability of the solution :
Four aphicide treatments are allowed in 2024 on sugar beets. Two molecules are used : one with a waiver request each year (120 days), will no longer be usable in 2025, and the second is a molecule for many crops with a high risk of emergence of resistance. The strategy tested in this project could replace some or all the aphicide treatments carried out according to the risk of each campaign. These strategies could help them to save aphicide treatments for campaigns with a low to moderate risk. In high-risk years, it could allow them to limit yield losses. The strategy falls into the category of indirect control/prophylactic methods with the main objective of reducing virus transmission by aphids, as opposed to direct control methods based on pest elimination. Thus, this strategy is part of the cultivation system transition by reconsidering sugar beet protection against aphids and yellows viruses.

Consortium :
This project is coordinated by the ITB, which provides operationnal management of the PNRI with INRAE which provides scientific management. Thanks to its expertise in sugar beet cultivation, it acts as technical support to the other partners. The project is based on the scientific expertise of the partners with complementary skills, from virus to farmer field.