Combination of field margin manipulation and genetic resistance to limit Aphis gossypii outbreaks and virus epidemics in melon crops
Résumé
Aphis gossypii is a major pest of Cucurbitaceae crops as much by causing primary damages (sap uptake) as by being an important vector of viruses. The Vat gene confers to the melon a resistance to the colonization by A. gossypii as well as a resistance to the not persistent viruses (CMV, WMV,..) transmitted by these aphids. It is however ineffective to block the transmission of the viruses carried by other aphid species. The use of Vat is thus generally coupled with aphicid treatments to limit the viral transmission by the not colonizing aphids. However, the progressive reduction of the usage of the phytosanitary products in the crop protection imposed by the evolution of the regulation (plan Ecophyto 2018) leads to look for new strategies integrating cultural practices and genetics for the management of the bioagressors. The bibliography suggests that the management of field margins (strips sown with non host grass or flower mixtures) could be an effective option to decrease 1) the aphid pressure (and thus the risk of bypassing Vat) by favoring the development of natural enemies and 2) the virus pressure by constituting a filter reducing the viral load of aphids before they reach the crop. The hypothesis tested in this project is that an adequate manipulation of the environment of the crop can contribute to regulate the populations of aphids and\or their viral load and therefore to reduce the risk of viral epidemics. The effect of three types of field margins (naked soil, grassy strips and flower strips) is evaluated on the efficiency of the Vat-mediated resistance.
Domaines
Sciences du Vivant [q-bio]
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