Distribution of pest nematodes on sugarcane in south Queensland and relationship to soil texture, cultivar, crop age and region

Five plant-parasitic nematode species were found to be widespread on sugarcane crops surveyed in south Queensland, namely Pratylenchus zeae, Meloidogyne javanica, Paratrichodorus minor, Helicotylenchus dihystera and Tylenchorhynchus annulatus. Apart from Meloidogyne, high nematode populations were found in most soil types, suggesting more extensive crop losses could be occurring than previously estimated. The most important pests were P. zeae and M. javanica, as they were often found at high densities and their pathogenicity on sugarcane is established. Mean densities for most nematode genera did not differ significantly between sugarcane cultivars, except that fewer Pratylenchus were associated with cultivar CP51-21 than other cultivars surveyed. The density of Pratylenchus in roots was significantly higher in plant crops than in ratoon crops, whereas the density of Paratrichodorus was highest in first and second ratoons.