Four soilless media, 1:1 (v/v) pine bark compost-perlite, volcanic cinder, 2:1 (v/v) cinder-peat, and a 1:2:1 (v/v/v) rockwool-cinder-peat, were evaluated in the greenhouse for their effects on the growth of Anthurium cultivars 'Alii and 'Midori and on the population increase of burrowing nematode Radopholus similis (BN). Nine months after inoculation with 2000 BN per plant, root weights of 'Alii differed among media. Plant growth expressed as shoot and root dry weight, root vigor, shoot damage, number of new leaves and flower number was less affected by nematode damage in cinder than in the other media. These effects were also more pronounced in 'Alii than in 'Midori. The role played by cinder in reducing BN damage was not due to improved plant growth, because uninoculated plants grew better in pine bark compost-perlite or rockwool-cinder-peat than in cinder. Orthogonal contrast analysis indicated that nematode damage on 'Alii was favored by the presence of organic matter in the med
