Cyst nematodes
Definition
Cyst nematodes (Globodera and Heterodera) are highly specialised in one or a few crops. These nematodes are found in all soil types and can survive for long periods.
Damage
Damage is caused by deterioration of the root system and disruption of the hormone balance of the plant. The most prevalent species in the Netherlands are the potato cyst nematodes, Globodera pallida, Globodera rostochiensis, and the beet cyst nematodes, Heterodera schachtii and Heterodera betae.
Life cycle
The eggs of cyst nematodes hatch when attractants are secreted by a host plant. There is a natural decline in this secretion, so the infestation slowly decreases each year, but this rate of decline varies among nematode species. Once a juvenile has invaded the roots of a host plant, the plant responds by forming feeder cells. At this point, the juvenile is no longer mobile and molts.
Female or Male
Food availability determines sex: well-fed juveniles become females, while those with less food become males. Males leave roots; females stay, swell, and form cysts containing up to 600 eggs. After fertilization and death, the female’s skin hardens into a protective cyst, allowing eggs to survive in soil for years.
Species of cyst nematodes in the Netherlands
* Globodera pallida and Globodera rostochiensis (Potato cyst nematode)
* Heterodera schachtii (White beet cyst nematode)
* Heterodera betae (Yellow beet cyst nematode)
* Heterodera groettingiana (Pea cyst nematode)
* Heterodera carotae (Pea cyst nematode)
* Heterodera crucifera (cabbage cyst nematode)
* Heterodera trifolii (Clover cyst nematode)
* Heterodera mani (Rye grass cyst nematode)
* Heterodera avenae (Oat cyst nematode)
* Heterodera bifenestra (Oval grass cyst nematode)
