Biological Relationship of Rotyleinchulus borealis on Several Plant Cultivars.

The embryogenic development of Rolylenchulus borealis, at 24-26 C, was completed on corn, in 12-15 days, and the life-cycle of the nematode from egg to egg required 35-40 days at 20-25 C. Juveniles remained in the soil as preinfective stages for 17-19 days before becoming adults. Only immature vermiform and swollen egg-laying females were found attached to corn roots. Eggs were laid in a gelatinous matrix on the root surface; the number of eggs per egg mass was 45 +/- 28 on corn roots. Bean, green pea, potato, sorghum, and sweet potato were also found to be hosts of R. borealis. The nematode established a permanent feeding site on corn root in an endodermal cell that became hypertrophied. Pericyclic cells close to the feeding site showed granular cytoplasm and nuclei with hypertrophied nucleoli. A cell wall ingrowth was also noted around the area of stylet penetration into the endodermal cell.