white, lemon-shaped with large egg-mass often almost
totally enveloping the female.
Head small, consisting of labial plate and a single annule.
Median esophageal bulb rounded with distinct valve.
pore behind the level of the median
81-119 µm from the anterior extremity.
Paired ovaries almost fill entire body cavity.
Vulval slit in a cleft on cone-top.
Cuticular pattern at mid-body reticulate.
Cyst: Mature cysts small,
lemon-shaped with distinct neck and vulval cone; neck
often twisted. Color changes from white to russet-brown
with no intermediate yellow stage. Wall-pattern consists
of irregular zig-zag lines forming a close network.
Subcrystalline layer present, but fragile.
Prominent vulval cone with gently sloping sides which
blend smoothly into the body contour.
Bullae absent. Underbridge about 90 µm long, bifurcate, slender,
unsclerotized and often lost during slide preparation.
Vulval slit, 43-51 (av. 47) µm long, occurs in a
recessed cleft on the top of the cone and often appears
partly open. Vulval lips unsclerotized. Fenestration
indistinct, ambifenestrate. Vulval bridge frequently
broken in older specimens.
Egg-mass large and usually filled with eggs, the egg-mass
often as large as the cyst.
Male: Vermiform with short, bluntly
Head offset, 7 µm long by 11 µm at widest point,
with 6-8 indistinct post-labial annules. Cephalic
framework robust. Anterior and posterior cephalids
level of second and sixth body annules, respectively.
Spear strong with rounded basal knobs.
Dorsal esophageal gland orifice 5-7 µm behind spear
Median esophageal bulb oval with poorly developed
valve plates which are 85-105 (90 µm) from anterior end.
Excretory pore 148-161 (av. 163) µm from head. Hemizonid
conspicuous, 2-3 annules long, located 6-9
annules in front of the excretory
Single testis uniformly packed with sperm and
averaging 59% of total body length.
Spicules arcuate with a bulbous anterior part and
tubular mid-part tapering into a twisted posterior
tip bidentate. Gubernaculum
field with four lines forming three bands;
outer lines crenate, outer bands
Dorsal esophageal gland
orifice 5-6 µm behind spear knobs.
Median bulb oval, but poorly developed. Median valve
plates 61-72 µm from anterior extremity.
field with four incisures forming three bands;
outer lines crenate, outer bands
obscure, 3-4 annules anterior to excretory
Genital primordium apparently consisting of two cells
and located 60% of body length from head. Vast majority
of juveniles exhibit typical Heterodera
tail shape, but a small number per cyst show variations.
The most common variation is the presence of 1-3
spherical refractive bodies within the tail, sometimes
with associated swelling. In a few cases, the tail may be
shortened to resemble that of a Meloidogyne
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Europe, Southern Africa, North America, Mexico (Escobar-Avila et al., 2018.
Associated with considerable yield losses in carrot production in Italy
Feeding site establishment and development
typical of genus.
Carrot, Daucus carota (wild and cultivated). Also reported on
Torilis leptophylla. also in the Apiaceae.
Juveniles from the egg-mass hatch within a few days, even in the
absence of a host plant, and may begin a second generation by
invading young rootlets. Infective juveniles ratined in cysts do not
emerge until 2-3 months after the brown stage has been reached.
Dehydrated egg-masses may persist in the soil either free
or adhering to the cyst or to pieces of root.
Root invasion takes place in 36 hrs. at 18-20 C. Development
of egg-sac starts about 4 weeks later. Some females even at
maturity remain embedded within the root. Egg-sac rapidly fills
with extruded eggs which are at first unembryonated, but later
contain fully developed juveniles.
Adult males may be found after about 30 days; they are
numerous and, in Italy, they were found free in the soil between
October and November (Ambrogioni, 1970, 1971).
On carrots sown in March and harvested in July (England), only
one generation developed, but on the main crop sown in May and
harvested in November, it is possible for two generations to
develop (Jones, 1950a). Two generations may also develop on
greenhouse-grown carrots (Stelter, 1969).
[Ref: CIH Descriptions of Plant-parasitic Nematodes, Set 5,
No. 61 (1975)]
Patchy growth, yellowish leaves; distortion of tap root, due
to early lignification, renders affected carrots unmarketable.
Lamberti, et al. (1974) observed that two applications of 1,3-Dichloropropene
made at 3 and 4 weeks prior to sowing, result in highest increase
in carrot yield.
Greco, et al. (1974) found that phenamiphos (500 kg/ha) or
dazomet (500 kg/ha) gave high yield increases with respect to
control. Acceptable results were also obtained with Di-Trapex
(300 l/ha) and 1,3-Dichloropropene (Telone) (400 l/ha).
A range of other nematicides
produce acceptable results, but
are not economically feasible to use.
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
CIH Descriptions of Plant-parasitic Nematodes, Set 5, No. 61 (1975)