Biocontrol of , the Causal Agent of Coffee Leaf Rust, by sp. NMA1017.

Coffee leaf rust (CLR), caused by , is considered a highly important phytosanitary problem in Mexico. Currently, there are few microorganisms used as biocontrol alternatives to chemical control of CLR in organic coffee fields in Mexico. This study evaluates the use of sp. NMA1017 as a biocontrol agent to inhibit the development of in in vitro and in vivo (greenhouse) experiments. urediniospores were placed on water agar plates, and then sp. NMA1017 was inoculated simultaneously or 8 h later. Urediniospores germination rate was reduced by 94% when the NMA1017 strain was inoculated simultaneously with the urediniospores and reduced by 38% when NMA1017 was inoculated 8 h later. Experiments with 8-month-old Bourbon coffee plants that were infected with showed that disease incidence was reduced by 38, 90, and 50% when NMA1017 was applied 8 days before, simultaneously, or 8 days after the application of , respectively. sp. NMA1017 also reduced the severity of CLR on the leaves by up to 62%. The germination urediniospores of other rust pathogens such as (maize leaf rust), (wheat leaf rust), f. sp. (black stem rust of wheat), (alfalfa leaf rust), and sp. (rosebush leaf rust) were also inhibited. Use of the potential biocontrol agent sp. NMA1017 might help reduce the application of chemical fungicides for the control of CLR, making coffee a more sustainable crop and providing management options for organic coffee growers.