a. borhani

In an etiological study on stunted, nursery grown maple seedlings, a species of root-lesion nematode (Pratylenchus vulnus) and two species of fusarium (Fusarium oxysporum and F. solani) were isolated from the infected roots. Interactions between the nematode and the two fungi in a complete randomized design with six treatments and four replications were carried out under greenhouse conditions. Nematodes were surface sterilized and reared on sterilized carrot discs. Then the maple seedlings at two-leaf stage were inoculated with a population density of 40 nematodes/100 gr soil in pots. The results indicated singnificant differences between the treatments. Seven months after inoculation, the treatments with nematode alone showed a high mortality rate of about 75% along with a severe increase in population up to about 11.2 and 1266 nematodes/gr of soil and roots, respectively. In treatments with nematode and each of the two-fungus species, the deleterious effects of fungi on nematodes were observed through decrease of nematode population. It was also shown that F. oxysporum was more effective than F. solani in nematode control.