In the attempt to exploit the potential of the monoecious fiber hemp cv. Futura 75 in new fields besides textile, cosmetics and food industry, its crop-residue given by leaves and inflorescences was subjected to hydrodistillation to obtain the essential oils. These are niche products representing an ideal candidate for the development of natural insecticides for the control and management of mosquito vectors, houseflies and moth pests. After GC-MS analysis highlighting a safe and legal chemical profile (THC in the range 0.004-0.012% dw), the leaf and inflorescence essential oils were investigated for the insecticidal potential against three insect targets: the larvae of Culex quinquefasciatus and Spodoptera littoralis and the adults of Musca domestica. The essential oil from inflorescences, showing (E)-caryophyllene (21.4%), myrcene (11.3%), cannabidiol (CBD, 11.1%), α-pinene (7.8%), terpinolene (7.6%), and α-humulene (7.1%) as the main components, was more effective than leaf oil against these insects, with LD50 values of 65.8 μg/larva on S. littoralis, 122.1 μg/adult on M. domestica, and LC50 of 124.5 μl/l on C. quinquefasciatus larvae. The hemp essential oil moderately inhibited the acetylcholinesterase (AChE), which is a target enzyme in pesticide science. Overall, these results shed light on the future application of fiber hemp crop-residue for the development of effective, eco-friendly and sustainable insecticides.

Crop Research Institute Drnovska 507 161 06 Prague 6 Czech Republic

Department of Agriculture Food and Environment University of Pisa Pisa Italy The BioRobotics Institute Scuola Superiore Sant'Anna Viale Rinaldo Piaggio 34 56025 Pontedera Pisa Italy

Department of Pharmaceutical and Pharmacological Sciences Natural Product Laboratory University of Padova Padova Italy

School of Pharmacy University of Camerino Camerino Italy

School of Sciences and Technology University of Camerino Camerino Italy

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