Ditylenchus destructor
| Potato rot nematode | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Tylenchoidea |
| Subclass: | Diplogasteria |
| Order: | Tylenchida |
| Superfamily: | Tylenchoidea |
| Family: | Anguinidae |
| Subfamily: | Anguininae |
| Genus: | Ditylenchus |
| Species: | D. destructor |
| Binomial name | |
|
Ditylenchus destructor Thorne, 1945 |
|
Ditylenchus destructor is a plant pathogenic nematode commonly known as the potato rot nematode. Other common names include the iris nematode, the potato tuber eelworm and the potato tuber nematode. It is an endoparasitic, migratory nematode commonly found in areas such as the United States, Europe, central Asia and Southern Africa.
Potato rot nematodes are microscopic worms approximately 1.4 millimeters long. Their life cycle takes place inside potato tubers where they eat starch grains. This causes the affected tissues to become brown and powdery, and the surface of the tuber becomes covered with dark patches with dry cracking skin. The nematodes live inside the living tissue where they aggregate rapidly as the fecund females each produce up to 250 eggs. They survive in stored tubers during the winter and can infect the stolons of planting material. After infection, the nematodes move throughout the plant tissue producing a pectinase enzyme, which causes cell degeneration and is the main causal agent of the rot observed. The soil plays only a secondary role in the transfer of this nematode.
The life cycle of Ditylenchus destructor lasts approximately 6 days As Ditylenchus destructor is an endoparasite, a majority of the life cycle occurs inside the host tissue. There are four molting periods and juvenile stages of development for Ditylenchus destructor with the first juvenile stage occurring within the egg. Females deposit eggs inside the tuber from their ovaries at which point the embryos begin undergo a cleavage process, beginning the first juvenile stage. Two and a half hours later the juvenile nematode can be seen through the egg wall, and 48 hours later the first larval stage has completed and hatching occurs. Hatching marks the molting into the second juvenile stage, and development continues until the next molting. In the third juvenile stage the sexual structures begin to develop and become visible. This development of additional structures causes large amounts of growth and elongation is seen in the nematode (especially in females who have more development occur). It is in the fourth stage where the sexual structures fully develop: vaginal development in females and testes development in males. At this point the nematodes undergo their final molting and enter the final, adult stage in their life cycle. After feeding on a host for some time, the females lay eggs inside the tuber, the eggs are fertilized by a male, and the cycle repeats.
As an migratory, endoparastie, Ditylenchus destructor females lay eggs throughout the plant tissue while moving from cell to cell. Once they have hatched, the juvenile nematodes will either move throughout the surrounding plant tissue or out of the plant from which they hatched to a nearby, healthy host.Ditylenchus destructor is not very mobile through soil though, so dispersal primarily occurs during harvest or transportation of the host when healthy tubers are in the immediate vicinity. If the nematodes exit the initial host, they most commonly infect the tubers of a new host; however, it is sometimes possible for them to infect the above ground parts of the plant and migrate to the tubers through the plant cells.
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Wikipedia