Plant-parasitic nematodes associated with rice in Ecuador.
The aim of this work was to analyze the frequency of occurrence, distribution, and population densities of plant-parasitic nematodes associated with rice in Guayas, Los Ríos, Manabí, El Oro, and Loja provinces, Ecuador. A total of 331 samples of roots and soil and 210 samples of paddy panicles were collected in 46 rice-growing areas. Nematodes were extracted from 10 g roots, 100 cm3 soil, and 100 seeds. The root-knot nematode, Meloidogyne graminicola, occurred at greatest frequency and had the highest population densities both in roots and soil. In irrigated rice plantations, Hirschmanniella oryzae was found most often in rainfed lowland rice, and Pratylenchus spp. were present at greatest frequency. Other nematodes identified in soil samples were species of Helicotylenchus, Criconemoides, and Tylenchorhynchus. Aphelenchoides besseyi was detected in dry seeds collected in the five provinces at varying population densities.