The use of corn as a rotation crop in integrated programs for controlling plant-parasitic nematodes has been widely recommended. In Brazil, where most of the commercial varieties and hybrids have been rated as resistant to root-knot nematodes for many years, its inclusion in cropping sequence strategies for the control of Meloidogyne incognita and mainly M. javanica became almost bligatory. At present, however, it is known that many genotypes are actually tolerant hosts for M. javanica, allowing the nematode to develop and reproduce in the roots, without causing root galls or plant growth reduction. A greenhouse/laboratory study was carried out to increase our knowledge of the anatomical changes induced by M. javanica in corn roots. Corn hybrid BR 106 (a suitable host) seedlings were individually inoculated with 10 000 second-stage juveniles and maintained in a greenhouse. After 60 days, slightly swollen and galled root pieces (1-3 cm long) were processed for light microscopy histol
