New trials: Trap crop for control of PCN in potato crops

Wednesday, 15 July 2020

Four group members of The Shropshire Potato Growers Discussion Group are hosting trials on their farm this year looking at trap crops as a method of PCN control.

Why is PCN a problem?

For potato growers in the UK one of the biggest threats to production and sustainability are the potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) which can result in significant yield losses.

Current control methods: 

Current PCN control methods involve use of the nematicides oxamyl and fosthiazate, applied at planting, which only protect one season’s crop yield, do not prevent PCN population increase and are hazardous to operators and the environment.  For conventional and organic growers, the alternative control options are either potato planting only one year in eight years minimum or use of G. pallida resistant cultivars of which there are only a few. 

Trap Crops method

An alternative cultural control method which has demonstrated significant promise is the PCN ‘trap crop’ Solanum sisymbriifolium (sticky nightshade). Whilst S. sisymbriifolium has the potential to reduce PCN population densities by 75-80%, the ideal establishment time is May/June and the crop has a track record of being difficult to establish. The area currently grown is small at ca. 100 Ha in Great Britain.  Similarly, another solanaceous species, Solanum scabrum (African nightshade) is a potential trap crop which appears to be easier for growers to establish, but currently lacks clear establishment guidelines in the UK. For more widespread uptake, both of these crops should be grown in-between two normal crop harvest and planting dates to prevent the loss of a cash crop in the rotation.

The new trials on trap control

Four group members of the Shropshire Potato Growers Discussion Group are hosting trials in 2020. They are all experienced at establishing over-wintered biofumigant crops and all have fields available for drilling at one of the required times. Other important factors are availability of irrigation to aid establishment if necessary and access to suitable drills.

An important objective of the work is to hold regular meetings to discuss the development of the experiments, results, relevant observations and the future directions of the research. These meetings will be attended by the hosts of the trial sites, other members of the Shropshire Potato Growers Discussion Group, the seed supplier (Produce Solutions), Andrew Wade (OptiGrow), Ivan Grove (Independent) and Matthew Back (HAU).

Treatments and methods

This field lab is looking to develop good establishment practice for the trap crops S sisymbriifolium and S scabrum when drilled after cereal harvest. Key aspects are date of drilling, weed control and drilling depth.

A randomised plot design will allow analysis by Harper Adams University.  


  • Two species: Solanum sisymbriifolium and Solanum Scabrum
  • Two planting dates: early July and early August
  • Two planting depths: 1cm and 3cm


  • Regular photograph records to provide a progress update and discussion point for meetings; from hand held and drone cameras.
  • Emergence counts on several dates to monitor first and final emergence speed and percentage;
  • Ground cover as measured by photography at approx. 50% leaf cover, 100% cover and pre- crop destruction; using an ‘easy leaf area’ app suitable for anyone with a smart phone.
  • PCN counts pre trap crop (Pi) and after trap crop destruction (Pf)

September 2020: Update Video 

S scabrum and S. sisymbriifolium plots drilled 29.6.2020

Dr Matt Back with S.sisymbriifolium plant drilled 29.6.2020