Distribution of root-knot nematode on coffee production in the Cerrado region of Minas Gerais state in Brazil.

Brazil is the largest coffee-producing nation in the world. Over 50% of the national production comes from the Minas Gerais state, with relevant contribution of the region covered by the Cerrado biome. Given the threat posed by root-knot nematodes (RKN, Meloidogyne spp.) to coffee production, we collected plant and soil samples from infested plantations across 16 counties and identified the species of this pathogen. Based on the female perineal patterns, male morphology, esterase phenotypes and SCAR markers, the species found were Meloidogyne exigua, Meloidogyne paranaensis, Meloidogyne incognita and Meloidogyne arenaria. The most prevalent species was M. exigua, occurring in 83.8% of the sampled sites, followed by M. paranaensis (19%) and M. incognita (4.9%). Mixed populations of RKN were observed in 7.7% of the sites, with the highest prevalence of M. exigua + M. paranaensis and M. paranaensis + M. incognita, followed by M. exigua + M. incognita. Meloidogyne arenaria was found in one site, in a mixed population with M. paranaensis + M. exigua. Strategies to prevent the spread of these nematodes to non-infested areas are highly recommended, particularly focusing on the most aggressive species such as M. paranaensis and M. incognita. [ABSTRACT FROM AUTHOR]