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New real-time PCR tests for Ralstonia and Xanthomonas in Pelargonium

Publicationdate: 26 januari 2024

As of January 1, we are introducing a new real-time PCR for detection of Ralstonia spp. in planting material of horticultural crops and for Xanthomonas wilt in Pelargonium.

Real-time PCR is a technique for rapidly amplifying DNA

This is done using pathogen-specific building blocks. The increase in DNA can be monitored digitally at any time. This makes it possible to confirm more quickly and with more certainty whether the pathogen is present.

Tests for Ralstonia

Brown rot in potato, Ralstonia wilt in rose or Pelargonium, these diseases are caused by bacteria belonging to the Ralstonia solanacearum species complex (RSSC). The variation within this species complex is large and is divided into four types (phylotypes).

There was already a test for this bacterium using the culture method. A new test has now been developed and approved by the NVWA for testing Ralstonia spp. using real-time PCR. This test takes a shorter time, which means that a result can be obtained sooner. If the result is positive or unclear, the culture method will still be carried out.

 Tests for Xanthomonas

The bacterium Xanthomonas hortorum pv. pelargonii (formerly Xanthomonas campestris pv. pelargonii), also called Xanthomonas wilt, is a very troublesome disease in Pelargonium. The disease is easily spread. The bacteria infect plants through wounds or directly through the leaves by splash spread. From there they grow quickly to the vascular bundles and then enter the entire plant via the vascular system. This causes the vascular bundles to become clogged, resulting in disrupted water transport, stunted growth and soon afterwards wilting if the plants evaporate a lot. At low temperatures, the bacteria multiply slowly and it takes a long time before symptoms become visible. However, dispersal between plants does take place during this latent period. By the time crop symptoms become visible, it is often too late to intervene. Clearing the crop is then the only option. The disease is difficult to recognize in several Pelargonium species and varieties. Sampling of symptomless material is the method to detect the disease in time.

The test can be performed in parallel with the RSSC test.

What tests do we offer?

  • Ralstonia spp. or Xanthomonas hortorum pv. pelargonii plant samples
    • Sample: 1-10 stem sections of 1 cm
    • Test fee: € 86
    • Test duration: 4-10 days
  • Ralstonia spp. or Xanthomonas hortorum pv. pelargonii lot samples
    • Sample: 11-200 stem sections of 1 cm
    • Test fee: € 100
    • Test duration: 4-10 days
  • Ralstonia spp. and Xanthomonas hortorum pv. pelargonii lot samples
    • Sample: 11-200 stem sections of 1 cm
    • Test fee: € 128
    • Test duration: 4-10 days
  • Ralstonia spp. water samples with new PCR confirmation test
    • Sample: 0,5 liter water
    • Test fee: € 61
    • Test duration: 12 days

For basic amounts see 2024 price list.

Naktuinbouw Laboratories supports sector

We continue to support the sector by developing new tests that help diagnose plants with symptoms or check for and guarantee freedom from certain viruses.

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