3 ways to manage the PCN population within a potato crop rotation

Potato cyst nematodes (PCN), also known as eelworm; can account for upwards of £25 million per year in losses in potato production in the UK.  There are two main species of PCN, Globodera pallida and Globodera rostochiensis.

With the ever changing landscape in relation to chemical controls for PCN and  PCN free land becoming more and more scarce; varietal choice is becoming more important as part of the decision making matrix when it comes to growing potatoes with a commercial end use.  Quality and marketable yield is dependent on effective Potato Cyst Nematode (PCN) control.

Soil sampling

Regular soil sampling and mapping of the areas affected is one way of effecting control.  Ideally, when sampling, take into account the range of species in terms of % infestation and also threshold infestation levels of each species.  PCN soil sampling  is a statutory requirement for seed potato production, but it is equally important that  ware potato growers also  champion best practice in terms of sampling protocols wherever possible,  in order  to help in the control of this key potato pest.

Varietal Choice

Focussing on varietal choice as a key driver within an IPM reduced armoury programme, it is important to realise that, if present, The PCN species must be  determined  and numbers quantified  prior to making the decision to grow a particular variety.

Potato varieties differ in their resistance or tolerance to the two species.  Therefore, varietal choice is both a varietal and integral part in the approach to Integrated Pest management (IPM).  Resistant varieties should be combined with other control measures as part of an integrated pest management strategy.

Varietal resistance or Tolerance?

Resistance

In simplistic terms, Varietal resistance is different to varietal tolerance in that a resistant variety stops the population from increasing and the egg count at the end of a crop cycle should be less. 

Tolerance

A PCN tolerant variety can be defined as its ability to produce a similar yield compared with that in a PCN-free soil under otherwise similar soil conditions.

it is important to note that use of a tolerant variety will not necessarily prevent a nematode population rising within a field and therefore should be considered with due caution. 

Using Decision Tools

The AHDB potato variety comparison tool is based on varietal information collated by SASA.  This is an important tool in the IPM armoury which has been developed using SASA variety information and can be used to assist growers in choosing the most suitable variety for their farm.  By using pest and disease resistance ratings this tool can aid in the mitigation in crop losses caused by Potato cyst nematodes.

More information is available in the AHDB Potato Variety Database (varieties.ahdb.org.uk). Varieties also vary in tolerance; that is, how well their yield withstands PCN attack.

Take-home points

All growers who grow potatoes should be sampling irrespective of the fact that potatoes have been grown in the fields before or not.

combine the use of resistant varieties with preventative measures and alternative control methods such as biofumigation and trap cropping, we could significantly reduce the economic impact of the pest.

Consider variety and whether resistance or tolerance is the pivotal factor in terms of choice and also end market use.

8 achievable components to applying integrated controls for PCN:

  • Choose clean seed
  • Machinery hygiene
  • Volunteer control
  • Longer rotations
  • Integrated pest management programmes
  • Varietal choice
  • Use approved chemical controls if appropriate, as part of an integrated pest control programme.
  • Consideration of end market use.

 

You can find further information on this topic on the following links:

Potato Variety Comparison Tool Potato Cyst Nematode (PCN) PCN Grower Guide PCN Sampling Guide Biofumigation for management of PCN

Antonia Walker

Senior Knowledge Transfer Manager - Potatoes
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