Ditylenchus destructor - Microscopic exam and molecular identification

Ditylenchus destructor is a plant pathogen endoparasitic nematode, known as "nematode putrefaction potato" or nematode potato tuber.

This microscopic nematode is 1.4 mm long. Its life cycle develops within potato tubers where they feed on the starch grains. This causes the potato tissue brown and powdery, and the tuber surface is covered with dark plates with dry and rough skin becomes. Nematode lives within living tissue rapidly form aggregates, each female produces as about 250 eggs. Survive in tubers stored for the winter and can infect the stolons of planting material. After infection, nematodes move through the tissue producing a pectinase causes cells degenerate resulting rot. Soil plays a secondary role in the transfer of these nematodes, since they are not very mobile across the floor.

Its life cycle lasts 6 days. The female lays eggs that are fertilized by males. Unlike other nematodes, Ditylenchus destructor does not have a resting phase in the cycle, so that environmental conditions have much influence on their habits. The optimum condition is a floor with a 28 ° C and lower or higher temperatures inhibit its movement and its life cycle. Wet soils are particularly favorable for its development and movement on the ground. Agricultural practices greatly influence the spread of this pathogen. When collected and transported stacked tubers it is provided that nematodes move from an infected to healthy tubers Tuber around, facilitating the spread.

In addition to potatoes, these nematodes may affect more than 100 species of different hosts, including alfalfa, carrots, garlic, beets, hops, mint, tomatoes, parsnips, rhubarb and ornamentals such as tulips and iris are included. These nematodes only attack the underground part of the plant, such as roots, bulbs, rhizomes and tubers.

The main symptoms are common to other hosts and potatoes are rotting and discoloration of underground plant tissues. In potatoes, the initial infection can be detected by the appearance of small white spots under the skin of the potato. As it progresses enlarge and darken with spongy appearance and hollows. Tubers develop areas of subsidence and dry skin, cracks and detached from underlying tissue. Later more discoloration that may be secondary to invasion by fungi, bacteria and free - living nematodes appears. It does not usually affect the area of the plant, although heavily infected plants are usually weaker, smaller and can be bent and discolored leaves.  

Microbiological tests recommended

  • 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