Heterodera goettingiana 

Contents

Rev 10/17/2023

Male:

• Vermiform, very short, bluntly rounded tail. Body curved position when heat relaxed, the posterior part often twisting through 90 degrees about the long axis.
• Cuticle regularly annulated, 4 incisures in lateral field, appears un-areolated under the light microscope, but is in SEM.
• Head offset with prominent head cap and 5 to 6 annules. Head skeleton hexaradiate, heavily sclerotized. Anterior and posterior cephalids at level of second and eighth to ninth body annules, respectively.
• Well developed stylet, anterior portion 45% of total stylet length, knobs rounded with anterior faces sloping backward. Stylet shaft, extending from basal plate of head skeleton for 60% of stylet length.
• Median esophageal bulb a slender ellipse with prominent crescentic valve plates.
• Dorsal and sub-ventral esophageal gland lobes distinct, both lobes extending beyond excretory pore, but subventral lobe longer, extending to 15% of body length from head. Dorsal gland nucleus prominent, sub-ventral gland nuclei obscure.
• Broad nerve ring encircling esophagus between median bulb and gland lobes.
• Hemizonid distinct, 2 annules long, usually 5-7 annules anterior to excretory pore,
• Testis single, about 50% of total body length, packed with dense, spherical sperm and terminating in a glandular-walled vas deferens with narrow lumen.
• Cloacal aperture small, surrounded by a raised collar-like lip.
• Spicules stout, curved with inner faces reflexed inward and interlocked proximally to form a tube. Spicule tips broad and tridentatebut difficult to resolve with light microscope, a
• Gubernaculum a simple rod.
• Phasmids and caudalids not observed.

Female:

• Body swollen, lemon-shaped, with projecting neck containing the esophagus and part of esophageal glands,\ Anterior part of neck irregularly annulated, remainder of body without annulations or lateral incisures, but covered with reticulate ridges forming a brickwork-like pattern. Head skeleton weak, hexaradiate.
• Anterior part of stylet about 50% of stylet length and often detached in preserved specimens, stylet knobs rounded.
• Median esophageal bulb large, sub-spherical, with prominent oval valve.
• Esophageal glands in broad lobe, often displaced by massively developed paired ovaries.
• Prominent excretory pore at base of neck.
• Vulva and tail region carried on an obtuse cone-shaped projection, the vulva a transverse slit surrounded dorsally and ventrally by thin-walled crescent shaped areas leaving the vulva on a thicker-walled bridge-like structure.
• Vagina supported proximally by strongly developed lateral bands of muscle.
•  Fenestral region surrounded by a zone of thickened cuticle. The fenestral region is at the posterior pole of the body with the anus in a dorsal position.
• Females are white, turning brown at death.
• Gelatinous egg sac, exuded through the vulval aperture, into which some individuals lay a few eggs (Jones, 1950).

Cyst:

• Lemon-shaped with protruding neck and vulval cone, but irregularly formed specimens are common.
• Ambifenestrate; a vulval bridge bearing the vulval slit and dividing the fenestra into two semi-circular semifenestrae.
• Underbridge present and the vagina remains as a sheaf-like structure between the vulval bridge and underbridge.
• Cyst wall dark brown and tough, with a thickened, strongly pigmented zone surrounding the fenestra.
• Bullae absent.
• Egg sac is usually lost from cysts, remains in soil.

Second-stage juvenile:

• Folded 3 times in egg. Vermiform, with regularly annulated cuticle,
• 4 incisures in lateral field along most of body, reduced to 3 at anterior and posterior.
• Head slightly offset with 2-3 annules, a dorsoventrally elongate oral disc and lateral lips bearing amphid apertures
• Stylet robust, knobs varying from smoothly rounded to slightly hook-shaped with recurved anterior surfaces.
• Anterior part of esophagus as in male.
• Esophageal glands in an elongate lobe, extending for 33% to body length from head; broad posteriorly, Dorsal gland nucleus prominent, sub-ventral gland nuclei indistinct.
• Nerve ring as in male. Hemizonid 2 annules wide, 1 annule anterior to excretory pore. Hemizonion less than 1 annule wide, 7 or 8 annules behind excretory pore.
• Tail tapering uniformly to a finely rounded terminus, posterior 60% of tail hyaline.

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

Pea crop infested by Heterodera goettingiana; patches of stunted and chlorotic plants.

Photograph from Di Vito (1991)