Females lemon-shaped, bearing the subcrystalline layer. They
pass through a pale yellow stage before developing into a dark brown cyst.
Rugose pattern a series of short, zigzag lines without order. Punctations
of cuticle fine, irregularly arranged. As many as 200 eggs may be
deposited in the egg-sac. Vulva averaging 49.7 u (43 to 56)
long. Bullae present.
Males 1.3 mm (1.1 to 1.4) in length, closely resembling
those of other Heterodera. Spear knobs massive, rounded.
Cephalids located dorsally and ventrally near the sixth and eighth annules.
Esophageal gland nuclei about one body width apart. Spicula bidentate.
Hemizonid about six annules anterior to excretory pore.
Second-stage larvae avarage 439.6 (373 to
490) u long. Cephalids near middle of head. Spear knobs
slightly rounded. Hemizonid adjacent to excretory pore.
Dorsal esophageal gland opening 4.0 (3.3 to 5.2) u behind spear
base. About half of tail length occupied by the hyaline portion.
Symptoms: Premature yellowing of the foliage on infested
area usually is the first obvious evidence of lethal populations of the
nemas, but previous to yellowing it is possible to locate the areas by
the reduced size and untrifty-appearing plants.
During years of abundant moisture and on fertile
soil, soybeans may produce an almost normal crop while harboring enormous
numbers of nematodes. This is especially true of crops following
rotations. Under these conditions there is a tremendous build-up
of the pest.
(Description- Thorne, 1961)