Nematode population densities at various distances from the trunk were determined for four species of tropical fruit trees: guava (Psidium guajava), avocado (Persea americana), mango (Mangifera indica), and 'Tahiti' lime (Citrus x 'Tahiti'). Sampling in the drip-line just inside the outer boundary of the tree canopy gave the best results in consistently detecting maximum levels of plant-parasitic nematodes for all four species of fruit trees tested. Significantly fewer nematodes were found nearer to the trunk in guava and avocado. In mango and lime no significant differences with location were observed, other than those associated with the trickle irrigation system. Sampling near the outlets of the trickle irrigation system, which were located near the trunks of lime and guava, revealed significantly lower numbers of nematodes than sampling near the edge of the canopy.
