Nematoda, Tylenchida, Pratylenchidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- P. penetrans is one of the 2 species of Pratylenchus which are particularly harmful, the other one being P. vulnus. They are characterized by their specific host-range and their ecological requirements.
- These nematodes parasitize almost all kinds of fruit tree, including peach, almond, apple, certain Citrus and cereals, floral plants, market garden plants, potato and vine.
However, unlike P. vulnus, P. penetrans does not attack walnut, fig or olive but may be harmful to hazel. It is an important parasite of the roots of various meadow Gramineae in oceanic climates.
In Holland, it causes severe damage to pasture land, hence the name meadow nematode. Conversely, P. vulnus has a preference for sandy soils in the South.
- These nematodes attack the external cells of radicles and penetrate the tissues little by little whatever the stage of development. They create cavities in which they reproduce and tissues may contain thousands of individuals.
They gradually make their way to parts of the parenchyma that are still sound, affected areas being rapidly destroyed by a characteristic necrosis. When conditions are unfavourable, e.g. the roots decompose, nematodes leave the root and travel freely within the soil until they come across another host root.
- The duration of the life-cycle may vary from 1 to 2 months and several generations may succeed one another.
- Pratylenchus causes the formation of deep necroses in the roots, encouraging attacks by secondary parasites, especially fungi, which infect the plant and finally mask the responsibility of the nematode for the observed fall in yield.
- Necroses appear on the roots of potato and pustules form on the tubers, whose value is then reduced.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.