Skip to main content Skip to navigation

Application of novel solanaceous plants for the management of potato cyst nematode population densities

Primary Supervisor: Dr Matthew Back, Crop & Environmental Sciences

Secondary supervisor: Dr Jose Gutierrez-Marcos, University of Warwick

PhD project title: Application of novel solanaceous plants for the management of potato cyst nematode population densities

University of Registration: Harper Adams University

The GB potato industry regard potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) as intractable pests of high economic importance.The unknown future of pesticide registration under tightening legislation, i.e. (EC) 1107/2009, highlights the importance of advancing research on non-chemical management methods. 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a species that was found in 95% of PCN infested sites in a survey of England & Wales in 2014-2017 (Dybal et al., unpublished). 

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. However, research needs to be conducted to evaluate the performance of various Solanum spp. under GB conditions in order to identify agronomic criteria for optimal performance. For instance, the position of the solanaceous species within the rotation will be crucial. Moreover, factors affecting emergence and establishment should be examined. 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 date, seed rate, sowing depth and the application of seed priming.
  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. In conjunction with ICIPE (Kenya), explore the chemical ecology of the root exudates
  5. Investigate treatments (such as phosphites) that stimulate root development

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. In order to increase root mass, and therefore PCN hatching, we will investigate treatments such as phosphites that are recognised for stimulating root growth

Reference:

  1. Chitambo O, Haukeland S, Fiaboe K, Grundler, (2019) Plant Disease doi.org/10.1094/PDIS-07-18-1193-RE

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

Contact: Dr Matthew Back, Harper Adams University