Nematode survey and biochemical characterization of Meloidogyne spp. in a main banana production area in Brazil

Brazil is the third leading banana producing country worldwide. It produces approximately 6.8 million tons in 550 thousand hectares, which represents a gross production value of 3.4 billion dollars per year. Bananas are affected by many pathogens, whereas nematodes are of main concern. Of 132 nematode species, approximately 54 are associated with the banana rhizosphere. These species are involved in the destruction of primary roots and damage to the fixation system, which results in toppling of the trees and/or reduced productivity. The main parasite species of banana trees are Radopholus similis, Helicotylenchus sp., Pratylenchus coffeae, and Meloidogyne sp. Taking into consideration the importance of banana growers in the Brazilian state of Bahia and the limited information regarding the distribution and presence of the dominant nematode species, in this study, we determined the occurrence of the main phytonematodes in banana producing regions and used isoenzyme characterization to determine the prevalent species (Meloidogyne spp). A total of 147 soil samples were collected in 36 municipalities in Bahia, representing nine regions. Approximately 65% of the samples were taken in rhizosphere areas of Prata subgroup cultivars (AAB), followed by Cavendish (22%) and Plantain (10%) cultivars, with the remainder taken from those of the Silk and Pisang Mas cultivars. Helicotylenchus multicinctus was found in 87.1% of the crops sampled, followed by Rotylenchulus reniformis in 63.3%, Meloidogyne spp. in 61.9%, Pratylenchus spp. in 2.7% and R. similis in 2.0%. Regarding the species of Meloidogyne, M. incognita was found in 41.5% of samples, followed by M. arenaria and M. javanica in 36.6% and 18.3% of the analyzed populations, respectively.