Efficacy of the volatile oil from water celery (Helosciadium nodiflorum, Apiaceae) against the filariasis vector Culex quinquefasciatus, the housefly Musca domestica, and the African cotton leafworm Spodoptera littoralis.

Water celery (Helosciadium nodiflorum, Apiaceae) is a common and invasive hydrophyte occurring in rivers and slow waters of Europe. In the past, it was consumed as a vegetable and spices, but currently it has mostly been abandoned. As a result, this plant produces an unexploited biomass occluding rivers and slow waters. With the aim to valorise water celery as an important biomass source for the development of botanical insecticides, in this work, we investigated the inhibitory effects of the essential oil hydrodistilled from its aerial parts against larvae of the filariasis vector Culex quinquefasciatus, adults of the housefly Musca domestica, and larvae of the African cotton leafworm Spodoptera littoralis. The essential oil, which was characterized by the insecticidal limonene (39.8%) and myristicin (35.3%), exerted important toxic effects on 3rd instar larvae of C. quinquefasciatus and S. littoralis and on adults of M. domestica, with LD50 of 50.4 μl l-1 , 116.7 μg larva-1 , and 45.1 (male) and 70.1 (female) μg adult-1 , respectively. The oil did not show any noticeable inhibitory activity on the acetylcholinesterase enzyme. Our findings add scientific evidences highlighting water celery as an important biomass source to be used for the control of insect pests and vectors of high economic importance.