The Fungicidal Effect of Essential Oils of Fennel and Hops against Fusarium Disease of Pea

Abstract

Modern integrated farming systems encourage the search for alternative (non-chemical), highly effective methods of plant protection. In this study, the fungistatic effect of fennel essential oil (FEO) and hop essential oil (HEO) on fungal growth and their ability to treat Fusarium wilt was investigated. The study was conducted in vitro and in pot experiments. The severity of infection was assessed by disease index (DI), presence of Fusarium culmorum gDNA (qPCR) and anatomical analyses of infected plant tissue using an optical (OM) and scanning electron microscope (SEM). Laboratory analyses showed that FEO inhibits mycelial growth of Fusarium fungi (F. avenaceum, F. culmorum, F. equiseti, F. oxysporum, F. poae, F. solani, F. sporotrichioides, F. tricinctum), Botrytis cinerea and Cylindrocarpon destructans more effectively than HEO. FEO at a concentration of 2000 ppm completely inhibited the growth of F. culmorum, F. poae and B. cinerea. Both essential oils reduced the severity of Fusarium wilt caused by F. culmorum in pea plants (DI, OM, SEM). The qPCR shows that both essential oils are also able to reduce the synthesis of trichothecenes in the tissues of infected pea plants. The results of the study suggest that FEO and HEO represent a broad spectrum bio-fungicidal agent that can be applied directly to plants at a concentration of 500 ppm, greatly reducing the level of infection.