Photo Gallery- Wyoming
Male. The male begins to develop in much the same manner
as the female. It first becomes an elongated, cylindroid body slightly
shorter than the length of the original larva from which it was formed.
The testis appears as a series of cells roughly arranged in rows, with
the terminus reflexed. From the indefinite mass of cells and granules
surrounding the testis the male body gradually takes form, finally appearing
as an obese wormlike organism flexed once within the cuticle. From
this third stage the male elongates until it is flexed three or four times
within the greatly expanded larval cuticle. It now possesses a well-developed
spear with strong basal knobs and all other organs typical of nematodes
of this sort. Development takes place in the root cortex, and after
the final moult the male emerges into the soil.
In length the males usually range between 1.3 and 1.6 mm. Annules of the lip region, three or four, including the labial disc. Spear 25 to 28 u long, with strong basal knobs. Lobes of esophageal glands extending back ventrally along the intestine. Testis single, outstretched; spicula bidentate, resting on a slightly arcuate, troughlike gubernaculum.
Larvae range from 450 to 500 u in length, with a general average of about 460 u as stated by Taylor (1957). However, under- and oversize larvae are not unusual, depending no doubt on the suitability of the host and on natural variation. Spear averaging about 25 u length, which usually is about the length of the hyaline portion of the tail.
Identification. Morphological differences between Heterodera
schachtii and its close relatives are difficult to demonstrate.
Taylor (1957) separates the species on the basis of average larval lengths
in microns: schachtii, 460; glycines, 484; trifolii,
502; galeopsidis, 518. While these measurements are no doubt
diagnostic in most instances, the possibilities of variants within a species
should not be overlooked. The muscle band supporting the cervix of
is a single one, while the muscle bands of the closely related trifolii
are furcate at their attachments on the body wall (Mulvey, 1957).
This is an exceedingly difficult character to determine, except on very
favorable specimens. Franklin (1940) determined that the distal ends
of the spicula are bidentate, a character which appears to be rather stable.
However, males of other species also have bidentate spicula. The
wide range of hosts for H. schachtii makes determination on the
basis of hosts of doubtful value.
(Description- Thorne, 1961)
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