Plant-parasitic nematodes associated with coffee (Coffea arabica L., Rubiaceae) in Ethiopia.
A survey of plant-parasitic nematodes in coffee was conducted on 132 sites of different agroecologies in Ethiopia. Samples from each site were collected during the wet season of 2004 and the dry season of 2006. Plant-parasitic nematode genera recovered were: Helicotylenchus, Scutellonema, Rotylenchus, Xiphinema, Heterodera and Tylenchorhynchus. Helicotylenchus predominated throughout the area (65-74%), followed by Xiphinema (29-40%). Heterodera occurred at a frequency of 8-10% and reached the highest population density of any nematode taxa with 3310 juveniles per 100 g soil. Nematode densities were generally lower in the dry season than in the wet season, however, relative abundance of nematode taxa was in the same order. A wide spectrum of free living nematodes belonging to 8 different families were also observed, of which Dorylaimidae, Cephalobidae and Rhabditidae were the most common. Nematodes considered to be of economic importance in coffee decline were not detected in this survey.