Inhibition of anthracnose symptoms in common bean by treatment of seeds with essential oils of Ocimum gratissimum and Syzygium aromaticum and eugenol

Abstract

Essential oils (EOs) of Ocimum gratissimum and Syzygium aromaticum and eugenol were applied to common bean seeds harvested from plants with anthracnose symptoms, at a dose of 80 mg Kg−1 of EOs and 64 mg kg−1 of eugenol, using soybean oil as a vehicle. The treated seeds were planted in pots and grown in a greenhouse. Seeds treated with EOs and eugenol did not differ from the water and soybean oil controls with regard to the percentage seedling emergence. After treatment with EOs, only 21.6% and 28.6% of O. gratissimum and S. aromaticum plants developed symptoms. Following treatment with eugenol, a primary component in both EOs, disease symptoms occurred in only 19.6% of the plants, suggesting that eugenol is responsible for the fungicidal action of EOs of O. gratissimum and S. aromaticum. The chemical composition of EOs is unknown. The potential of EOs for controlling Colletotrichum lindemuthianum, responsible for anthracnose disease of common bean, is reported here for the first time.