Studies on the host range of Ditylenchus dipsaci in Morocco.
Severe damage due to D. dipsaci was observed on garlic, onion, peas, lucerne, sugarbeet and oat during surveys conducted in different regions of Morocco from 1991 to 1999. The infestation rate in these crops was high and ranged from 55 to 100%. The nematode reproduces very well on garlic on which more than 11 000 specimens per plant were found. Eleven out of sixty weed species found in fields of faba bean were infested to different extents by the nematode. Avena sterilis, Orobanche crenata, Vaccaria pyramidata [V. hispanica] and Verbena supina were good hosts for the giant race. Measurements of the lengths of adult and pre-adult stages, extracted from the surveyed crops, appear to be the normal race of the nematode; the measurements of nematodes extracted from V. hispanica appear to be the giant race.