Distribution and biology of Ditylenchus dipsaci and Aphelenchoides ritzemabosi in alfalfa grown in Colorado. Nematropica 31:11-16. A survey was conducted in 14 major alfalfa producing counties of Colorado (USA) to determine the distribution of Ditylenchus dipsaci and Aphelenchoides ritzemabosi . Both nematodes were found in six counties while neither was found in three. D. dipsaci occurred exclusively in three counties, and only A. ritzemabosi was found in two others. In addition to the survey, the response of four cultivars of alfalfa (Pioneer 5312, Pioneer 5364, Pioneer 5454, and Ranger 5-1153) to both nematodes was evaluated in greenhouse experiments, where a mixture of both nematodes was used as innoculum. Under these conditions, the four entries showed a high percentage of symptomatic plants, with symptoms ranging from slight to severe stem swelling and distortion. A field study designed to evaluate the effect of Furadan 4F as a means of nematode control showed that this pestici
