Ditylenchus dipsaci: Microscopic exam; Molecular identification (sequencing).

Ditylenchus dipsaci: Microscopic exam; Molecular identification (sequencing).

Ditylenchus dipsaci is a microscopic nematode 1.5 mm in length, plant pathogen that infects mainly onions, garlic and leek (Allium species), but can also affect carrots, beets, strawberries, peas, pumpkin, rhubarb , alfalfa, oats and ornamental bulbs like hyacinths or tulips. It is known as nematode stem, the eel worm stems and bulbs, or swelling of the onion. It is one of the most damaging parasitic nematodes worldwide plants. When an infestation occurs finishes with a 60 to 80% of the cultures. They have differentiated biological about 30 races are distinguished primarily by their preferred host, but that are difficult to distinguish morphologically.

This nematode enters the plant from soil through plant wounds or stomata and occasionally infects seedlings and seeds. Lives in the leaf cells of onion or garlic skins and between the bulbs, which feed on the cell sap and multiply. The female lays about 250 eggs in a station and grown 6 generations under optimum conditions when the temperature is 15 to 20C.

The plants have decreased growth, bulbs discoloration and swelling of the stems. Penetrating through the wound or plant stomatal creates gaps or defects in the growing plant, which also allows entry of fungi and bacteria. Leaves begin to curl onions, garlic leaves turn yellow and die, the skins of onions or garlic are lost, and the necks of the bulbs are cracked. The continuous development in infected bulbs during storage.  

microbiological testing

  • Microscopic examination to identify according to their morphological characteristics.
  • Molecular diagnosis when there are no adults, only juvenile forms, or to differentiate from other species.

Tests in IVAMI

  • Microscopic observation and identification.
  • Molecular diagnosis (PCR) when no adults or to differentiate from other species.

Delivery term

  • Microscopic identification: 24 hours.
  • Molecular identification: 3 to 4 days.

Type of sample

  • Plant bulbs with injuries.

Sample preservation

  • Room temperature inside a plastic bottle tightly closed with some moisture to prevent drying (eg., Piece of paper dampened with water).

Cost of the test