Impact of farnesol nanoformulation on the movement of melon aphid and the spread of aphid-transmitted viruses

Resumen

The management against Aphis gossypii Glover (Hemiptera: Aphididae) and aphid-transmitted cucumber mosaic virus (CMV, Cucumovirus) and cucurbit aphid-borne yellows virus (CABYV, Polerovirus) relies on synthetic pesticides and natural enemies, which can limit the spread of persistently-transmitted viruses but enhance non-persistent viral transmission. Nanoemulsions of biopesticides can help prevent insect resistance and shortage of authorized active ingredients. They can also solve problems associated with the formulation of natural substances. The phytotoxicity of nanoformulations of farnesol and aniseed was evaluated on melon plants. Farnesol caused brown circular sports and malformations on treated leaves that disappeared 2-4 weeks after application. The settlement and movement of A. gossypii were studied with EthoVision video tracking. The application of natural actives altered aphid behavior, increasing their movement and reducing the time they spent on plants. The primary and secondary spread of CMV and CABYV was evaluated under greenhouse conditions. Pesticide application before aphid release did not prevent the primary spread of non-circulative CMV, but reduced the spread of persistently-transmitted CABYV. Farnesol nanoemulsion is an encouraing option but its activity might be reinforced with the introduction of natural enemies. Our findings highlight that the application of respectful alternatives must be accompanied with an extensive insight of their individual biological features and impacts toward targeted pests and host plants.