Soil abiotic factors associated with Meloidogyne spp. and Pratylenchus spp. populations in sugarcane

Abstract

Summary Meloidogyne spp. and Pratylenchus spp. are the most damaging plant-parasitic nematodes to sugarcane and the knowledge of soil characteristics that influence the occurrence of these pathogens can be useful in their management. With the objective to investigate the relationships between soil variables and populations of Meloidogyne spp. and Pratylenchus spp. in sugarcane fields, root-zone soil and root samples were collected from 20 farms located in 16 municipalities in Alagoas state, Brazil. The multivariate regression tree technique was used to model the population density’s response variables for Meloidogyne spp. and Pratylenchus spp. in the root-zone soil and the roots according to sugarcane cultivars, soil organic matter, and soil chemical and physical variables. The results showed the existence of associations between soil factors, sugarcane cultivars and populations of nematodes. Root samples from soils with K > 37.79 mmolc dm−3, Al < 5.93 mmolc dm−3 and sugarcane ‘RB92579’, ‘SP753046’, ‘SP813250’ and ‘SP921631’ showed the lowest Pratylenchus spp. population densities. However, the lowest densities in the root-zone were found in soils with sum of bases > 1.91 mmolc dm−3, Ca:Mg ratio < 1:2 and soil organic matter < 10.7 g dm−3. The lowest population densities of Meloidogyne spp. in roots were associated with sugarcane ‘RB92579’, ‘RB93509’, ‘RB98710’, ‘SP791011’ and ‘SP921631’ and soil aggregate mean diam. > 0.48 mm, while root-zone densities were minimum in soils with P > 28.59 mg dm−3. This information should support further studies to investigate the effect of each variable on populations of Pratylenchus and Meloidogyne.