Zanjan province with 39398 km2 area and 2689 villiges is one of the important agricultural and animal husbandry center in Iran.
In a survey to study the pattern of infection 452 samples were taken from different alfalfa fields during 1987 1989.
The nematodes inside stem and soils were extracted using DE, Grisse centrifuge technique (DE, Grisse, 1986) and numbers of different stages of nematodes in 20 gram material and 500 gram of soil were counted.
The results showed that about 50.3 percent of the alfalfa fields in Zanjan province are infected with this nematode. The rates of infestation varied in different districts, are as follow:
50.3% in Zanjan, 43.7% in Qazvin, 61.5% in Abhar, 81.8% in takestan and 58.3% in khodabandeh district.
The results revealed that the alfalfa nematodes were distributed in almost all districts of Zanjan province. So, it is necessary to apply an efficient and economical method to prevent the spreading of the disease and reducing the population of this nematode.