Inhibitory Effects of Plant Essential Oils on Xanthomonas citri pv. mangiferaindicae, Causing Bacterial Black Spot on Cashew and Mango in Burkina Faso

Bacterial black spot is a major constraint in mango and cashew production in Burkina Faso. It is caused by Xanthomonas citris pv. mangiferaeindicae (XCM). It is necessary to identify sustainable management strategies of this constraint. The aim of this study was to investigate in vivo and in vitro the antibacterial efficacy of essential oils (EOs) of Cymbopogon citratus and Ocimum gratissimum against XCM. The antibacterial effects of both the EOs at different concentrations were evaluated using the strains LM6.1 and LH127.2 of XCM isolated from cashew and mango, respectively. Copper hydroxyde was used as chemical control. Before, the plant-toxicity threshold of formulas of EOs was assessed. The results showed that the lowest dose of EO formula to be used for antibacterial activity essays was 5%. In vitro and in vivo, the EOs of O. gratissimum and C. citratus had significant inhibitory effect on growth of both LM6.1 and LH127.2 strains of XCM with concentrations ranging from 0.5 to 5%. Taken together, The EO of O. gratissimum was more efficient than the EO of C. citratus. Thus, these EOs could be an alternative to the use of chemicals against mango and cashew pathogenic bacteria.