Abstract
PurposeWeeds and fungi are serious pests of a wide range of agricultural crops. In addition, due to the negative environmental impacts of chemical pesticides, these pests are developing important resistance against them. Therefore, one alternative method to control pest is the use of plant derived active molecules; particularly essential oils and phenolic compounds have been an increasing interest in their safe and environmentally-friendly application to crops, as a powerful alternative to chemical pesticides. MethodsThe present investigation studied the chemical composition of Foeniculum vulgare essential oil (Eos) and methanol extract (ME) respectively by GC/MS and LC/MS analysis. In second step, we evaluated their phytotoxic activity against Sinapis arvensis, Trifolium campestre, Lolium rigidum and Lepidium sativum and their antifungal potential was studied in vitro against five phytopathogenic fungal species (Fusarium oxysporum sp. Lycopersici, F. culmorum, F. oxysporum 184, F. oxysporum mathioli and F. redolens). ResultsHigh amounts of monoterpenes were detected in Eos, consisting mainly of estragole (76.2%), alpha-thujone (9.6%) and limonene (8.6%). LC/MS analysis of ME allowed to the identification of 18 phenolic compounds distributed in eight phenolic acids, one non phenolic acid and nine flavonoids. Seed germination and seedling growth of weeds and crops were determined in Petri dish bioassay at different doses with reference to a negative control and a positive control (glyphosate). Fennel Eos and ME completely inhibited germination and seedling growth of tested crops and weeds in a dose-dependent manner. Data obtained with Fennel Eos and ME are similar to the activity of glyphosate. For the antifungal activity, the oils and the extract showed interesting variable activities depending on the dose and the strain tested. The best activities were obtained with Eos. ConclusionTaken together, these results indicate that Fennel molecules have phytotoxic and antifungal properties that could be used as natural bio-pesticides for weeds and fungi management.