Heterodera carotae
Encyclopedia
Heterodera carotae, is a plant pathogenic
nematode
commonly known as the carrot root nematode or carrot cyst nematode. It is found in Europe, Cyprus and India and is considered an invasive species
in the United States. It causes damage to carrot
crops and is very specific in its choice of hosts
, only infecting Daucus carota and Daucus pulcherrima.
is lemon-shaped, white at first later becoming reddish-brown, with a distinct neck.
are found in the cysts attached to the root systems of carrot plants and in plant debris and contaminated soil. Some hatch soon after the cyst is formed and the second stage juveniles disperse through the soil and invade young rootlets by piercing through the epidermis with their stylets. Most, however, remain in the cyst for two to three months after it has turned brown. At first the male and female juveniles look similar, both being threadlike and growing to 1.5 millimetres long. Four weeks after invasion the juveniles moult and the females become mature. An egg-sac begins to form and soon fills up with from 200 to 600 eggs. As the sac swells it bursts through the root tissues. The males move through the soil searching for females, and after fertilisation, the juveniles begin to develop inside the female's body. She dies and her cuticle hardens to become a cyst still attached to the root.
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
commonly known as the carrot root nematode or carrot cyst nematode. It is found in Europe, Cyprus and India and is considered an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in the United States. It causes damage to carrot
Carrot
The carrot is a root vegetable, usually orange in colour, though purple, red, white, and yellow varieties exist. It has a crisp texture when fresh...
crops and is very specific in its choice of hosts
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
, only infecting Daucus carota and Daucus pulcherrima.
Distribution
In Europe this nematode has been recorded in Germany, France, Portugal, Italy, Hungary, Poland, Sweden, Russia, the Czech Republic, the Netherlands, the United Kingdom and Ireland. It has also been found in India and Cyprus and at several locations in the state of Michigan in the United States of America.Morphology
The female carrot cyst nematode is white and lemon-shaped, averaging 400 µm by 300 µm, with a pair of ovaries occupying most of the body cavity. The male is threadlike, short with a rounded tail and a single testis averaging 60% of the body length. The mature cystCyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
is lemon-shaped, white at first later becoming reddish-brown, with a distinct neck.
Life cycle
EggsEgg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
are found in the cysts attached to the root systems of carrot plants and in plant debris and contaminated soil. Some hatch soon after the cyst is formed and the second stage juveniles disperse through the soil and invade young rootlets by piercing through the epidermis with their stylets. Most, however, remain in the cyst for two to three months after it has turned brown. At first the male and female juveniles look similar, both being threadlike and growing to 1.5 millimetres long. Four weeks after invasion the juveniles moult and the females become mature. An egg-sac begins to form and soon fills up with from 200 to 600 eggs. As the sac swells it bursts through the root tissues. The males move through the soil searching for females, and after fertilisation, the juveniles begin to develop inside the female's body. She dies and her cuticle hardens to become a cyst still attached to the root.