Pythium violae - Understanding the ecology and epidemiology to enable disease management in carrot crops


FV 432 - Pythium violae - Understanding the ecology and epidemiology to enable disease management in carrot crops

Start Date: 
Completion Date: 
Project Leader: 
Dr John Clarkson, University of Warwick
FV 432

Industry representative: Keith Mawer, Strawsons Ltd

HDC project cost: £148,352


The Problem:

Cavity spot is a major disease of carrots in the UK which is caused mainly by the soilborne oomycete pathogen Pythium violae. Despite being soilborne, control of cavity spot relies on the application of foliar fungicides but levels of control can vary and enhanced degradation may also occur in some soils. Long rotations between carrot crops are recommended (but not always possible) although some experiments have suggested there was no build-up of disease over four years of continuous carrot cropping.
Although P. violae has been studied extensively at times in the past, progress has always been hampered by the lack of effective procedures for detection and quantification of the pathogen in soil. However, a quantitative PCR assay for P. violae has been developed recently (FV353) enabling a preliminary understanding of pathogen dynamics in soil and the effect of some abiotic and biotic factors. However, there are still fundamental gaps in our knowledge concerning the epidemiology of P. violae and how it interacts with its environment and hosts. Effective tools and methodologies for P. violae research are also still lacking including further optimisation / development of the qPCR to make it more robust.
Aims and objectives:
This PhD project will address some of these issues and will aim in particular to understand the role of soil microbial communities in cavity spot disease development/suppression as well as develop experimental techniques to allow new potential control measures to be assessed under controlled conditions. The two major aims are:
1. To develop effective tools for P. violae research
2. To investigate P. violae dynamics, ecology and interactions with soil microbiota