Characterization, pathogenicity, and reproduction of Meloidogyne enterolobii populations parasitizing vegetables in Sinaloa, Mexico

Meloidogyne enterolobii is an emerging species and is considered the most damaging among root-knot nematodes due to its high reproduction and ability to overcome the resistance of various crops. However, there are few studies on the differences in reproduction and pathogenicity in different populations of this species. This study aimed to morphologically and molecularly characterize M. enterolobii populations present in vegetable-producing areas in Sinaloa, in addition to determining their pathogenicity and reproduction in tomato (Solanum lycopersicum L.), chili pepper (Capsicum annuum L.), and cucumber (Cucumis sativus L.) plants. For this, tomato and chili pepper roots with galls were collected from eight horticultural fields in Sinaloa (Mexico), distributed in the municipalities of Culiacán, Navolato, Elota, Guasave, Mazatlán, and El Rosario. The identity of the populations was verified by combining morphological and molecular characterization. The pathogenicity and reproduction of the populations were determined in 21-day-old plants of two cultivars each of chili pepper (cvs. Revelation and Orizaba), tomato (cvs. Aguamiel and Imperial), and cucumber (cvs. Maximo and Azulan), inoculating a total of 12 plants of each cultivar for each population of M. enterolobii with an inoculum dose of 4500 eggs/plant. For each population, the gall index and reproduction factor were determined at 21, 28, and 35 days after inoculation (DAI) in two independent experiments. All populations induced gall symptoms from 21 DAI, and at 28 DAI egg masses were observed in all cultivars used. However, at 35 DAI, the two cucumber cultivars showed a higher number of galls and egg masses, with a reproduction factor twice that of the chili pepper cultivars. There was no significant difference in pathogenicity and reproduction among the eight populations of M. enterolobii; however, it was observed that the populations showed a higher gall index and reproduction factor in cucumber plants compared to chili pepper and tomato plants.