First report of sesame spot caused by Xanthomonas campestris pv. sesami in Sinaloa, Mexico

A new disease on sesame (Sesamum indicum L.) plants was observed in the municipalities of Ahome, El Fuerte and Choix in the state of Sinaloa, Mexico during the summer of 2014. The disease occurred during the rainy season (August–September) when temperatures ranged between 27–40°C. The symptoms were lesions on leaves, petioles, stems and capsules. Up to 100% incidence was observed, and up to 50% of the foliage exhibited symptoms under field conditions. Isolations were made from leaves and a bacterium was consistently recovered on nutrient agar medium. Based on physiological and biochemical tests, as well as sequences from three different DNA regions, the bacterium was identified as Xanthomonas campestris pv. sesami. Pathogenicity tests confirmed the ability of select isolates to cause symptoms similar to those observed under field conditions.