Occurrence of Meloidogyne morocciensis parasitizing beetroot in Brazil

Beetroot plants cv. Boro exhibiting multiple root galls similar to those symptoms associated with root-knot nematodes (RKNs) were detected in the municipality of Rio Grande, Rio Grande do Sul state, Brazil. The nematode identification was based on an integrative taxonomy. Perineal patterns of females were similar to Meloidogyne arenaria and M. incognita whereas isoenzymatic phenotypes alpha-esterase A3 and malate dehydrogenase N1 were typical to M. morocciensis. Measurements of second-stage juveniles and males corresponded to the same species. Beetroot plants inoculated with 2.000 specimens of RKN showed reduction of fresh weight of shoots (37%) and roots (30%). The nematode reproduction factor was 11.9. Our study provides the first evidence that M. morocciensis causes root-knot disease in beetroot cv. Boro in Brazil and elsewhere.