Molluscicidal activity of four Apiaceae essential oils against the freshwater snail Radix peregra

Snails of the family Lymnaeidae are an essential link in the transmission of zoonotic diseases. Radix peregra is a European freshwater snail and a susceptible intermediate host of Fasciola hepatica , the causing agent of fascioliasis. Essential oils (EOs) extracted from Anethum graveolens (dill), Cuminum cyminum (cumin), Foeniculum vulgare var. vulgare (bitter fennel) and Petroselinum crispum (plain leaf parsley) were characterized by GC and GC–MS. Seven EOs and 11 constituents were first screened through a single-dose bioassay against R. peregra (10 mg L −1 for juveniles and 50 mg L −1 for egg masses and mature snails). EOs from parsley, cumin and bitter fennel (leaves plus stems) were highly active towards eggs and adults at 50 mg L −1 . Subsequently, dose and time–lethality bioassays were performed against adults to determine lethal parameters (LC 50;90 and LT 50;90 ). Estimated 48 h LC 50s varied from 13.7 to 46.5 mg L −1 , with P. crispum fruits EO exhibiting the most significant activity. EOs from cumin fruits and bitter fennel infrutescences, and cuminaldehyde, were the most time-effective treatments when assessed by continuous exposure (LT 50 for a 50 mg L −1 dose = 15.1, 19.3 and 19.5 h, respectively). A short-time exposure (8 h) to bitter fennel EOs was effective for the control of adults (LT 50 ≤25 h). The present study uncovers the potential of four well-known Apiaceae species as natural sources of biomolluscicides.