Effect of population densities of Meloidogyne incognita on growth of susceptible and resistant totamo plants

Meloidogyne incognita (Kofoid et White) Chitw., poses a serious threat to tomato (Lycopersicon esculentum Mill.) cultivations in Italy, especially in sandy soil (Di Vito, 1979). Investigations carried out under field and glasshouse conditions in Apulia showed tolerance limits of a susceptible and a resistant tomato cultivar to M. incognita of 4 and 3.3 eggs and juveniles/ml soil and a minimum relative yield of 0 and 0.77 respectively (Di Vito et al., 1981; Di Vito and Ekanayake, 1983). Similar results were obtained by Barker et al. (1976) in USA. In Italy tomato is either transplanted or sown. This study was undertaken to investigate the effect of population densities of M. incognita on yield losses of resistant and susceptible varieties of tomato transplanted and sown in soil artificially infested with the nematode.