Skip to main content Skip to navigation

Development of a sustainable trap cropping approach for the management of potato cyst nematode (Globodera spp.) infestations

Primary Supervisor: Dr Matthew Back, Harper Adams University

Secondary supervisor: Professor Frank Vriesekoop, Harper Adams University

PhD project title: Development of a sustainable trap cropping approach for the management of potato cyst nematode (Globodera spp.) infestations

University of Registration: Harper Adams University

Project outline:

Potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) are intractable pests of GB potato crops having the potential to cause up to 80% yield loss, while persisting in field soil for 20 years or longer. Management of PCN is achieved through crop rotation (PCN decline), selection of resistant potato varieties and the application of nematicides (chemical control). Nematicide options are limited and may face removal under tightening pesticide legislation. Moreover, only two of the ten most planted potato cultivars have resistance to G. pallida, a species that was found in 95% of PCN infested sites in a survey of England & Wales in 2014-2017 (Dybal et al., unpublished). Considering the weaknesses in current management approaches, sustainable non-chemical approaches are urgently needed.

Nematode trap crops are described as ‘poor plant hosts’ that can significantly limit nematode multiplication and reduce existing soil populations substantially. Previously, Solanum sisymbriifolium (sticky nightshade) was investigated but a number of issues, such as establishment and available growing period, restricted its use. More recently, alternative solanaceous trap crop candidates have emerged through research conducted for the AHDB and a PhD project in Kenya. Species such as S. scabrum, S. villosum and S. melanocerasum appear to have strong potential for trap cropping in GB potatoes. For example, S. scabrum has been shown to suppress PCN populations by >80% and may accelerate the decline of residual soil populations. Solanum scabrum, also known as African spinach, is particularly interesting as it has potential for being a dual-purpose crop; providing a harvestable product (spinach leaves) while at the same time helping to suppress PCN population densities. Research is required to determine a model system for growing Solanum scabrum or other PCN trap crop species, that are fit for human or animal consumption, under UK conditions. This multidisciplinary project will consider mechanisms of PCN suppression and trap crop agronomy in addition to the food safety and nutrition of harvested biomass. The objectives are as follows: -

  1. Conduct in-vitro studies to examine the effect of root leachates from the Solanum on PCN hatching and juvenile mortality.
  2. Monitor PCN population densities pre-drilling and post-incorporation of Solanum species and cultivars in glasshouse and field experiments. Experiments will be conducted on factors such as sowing and harvest date, seed rate and sowing depth.
  3. Based on GPS coordinates of the field plots from objective 2, resample the field sites to assess decline rates of the PCN populations previous exposed to Solanum
  4. Assess the glycoalkaloid content of harvested leaves to establish suitability for human consumption
  5. Assess the nutritional qualities of harvested leaves e.g. carbohydrates
  6. Investigate treatments that stimulate root development E.g. phosphites)

Methodology

  1. Using root leachates collected from the candidate Solanum, a series of juvenile mortality and hatching experiments will be conducted. Juvenile mortality experiments will be undertaken to determine the toxicity of leachates (allelopathy) whereas hatching experiments will provide detailed information about the emergence of juveniles from the cysts.
  2. Initially, glasshouse experiments will be conducted to compare the performance of Solanum spp on PCN population dynamics. Based on the results, field experiments will be conducted in East (Lincolnshire) and West England (Shropshire). Experiments will consider factors such as different planting date, seed rates, sowing depths and primed versus unprimed seed. Encysted eggs will be assessed using a trehalose assay to determine viability. All field plots will be marked with GPS so that the plots can be resampled and assessed in the following year to measure decline rates.
  3. To investigate differences in the performance of candidate Solanum, the student will conduct qualitative analysis of the root diffusates using HPLC. Hatching factors such as solanoecleptin A, α-solanine and α-chaconine will be assessed and compared. Equally, allelopathic (nematicidal) compounds will be investigated to examine any effects on the juvenile nematodes and infectivity.
  4. To investigate the suitability of the trap crop Solanum scabrum (aka African spinach) as a food crop with regards to food safety and nutritional value. Recent research (Yuan et al., 2020) has shown that African spinach is safe to consume with regards any potential antinutritive alkaloids and sapogenins, and can provide a nutritional salad leaf crop. This work will aim to confirm that Solanum scabrum, as a trap crop, is safe for human consumption and will explore its nutritional properties and processing abilities as a human food
  5. In order to increase root mass, and therefore PCN hatching, we will investigate treatments such as phosphites that are recognised for stimulating root growth

References:

  1. Chitambo O, Haukeland S, Fiaboe K, Grundler, (2019) Plant Disease doi.org/10.1094/PDIS-07-18-1193-RE
  2. Yuan, B., Dinssa, F.F., Simon, J.E. and Wu, Q., (2020) Food Chemistry, 312, https://doi.org/10.1016/j.foodchem.2019.126030.

BBSRC Strategic Research Priority: Sustainable Agriculture and Food: Plant and Crop Science

      Techniques that will be undertaken during the project:

      1. Sampling, extraction and enumeration of plant parasitic nematodes (i.e. cyst nematodes) from soil
      2. Molecular diagnostics (Real time PCR)
      3. Chromatography - HPLC
      4. In-vitro assessments of potato cyst nematode hatching and mortality
      5. Field experimentation – design, management, assessments and analysis
      6. Methods for assessing PCN viability i.e. trehalose assay

      Contact: Dr Matthew Back, Harper Adams University