Assessing the Biocontrol Potential of Pythium oligandrum Against Potato Late Blight

Sammanfattning

Potato late blight, caused by the oomycete Phytophthora infestans, poses a significant threat to potato crops worldwide. Infection leads to severe yield losses and poses a great challenge to agriculture, necessitating effective and sustainable management strategies. Current control measures to manage the disease and spread of the pathogen primarily rely on chemical fungicides, which raise concerns due to several associated risks including the development of resistance, adverse effects on non-target organisms and ecosystems as well as potential human health risks. Considering these challenges, the search for sustainable management alternatives has become increasingly important. Pythium oligandrum, a soilborne oomycete, is recognized for its potential as a biological control agent against various plant pathogens. It employs multiple mechanisms, including mycoparasitism and the induction of plant defence responses. The use of P. oligandrum in an integrated pest management strategy aligns with the goal of reducing dependence on pesticides while promoting sustainable agriculture. This study assesses the potential of P.oligandrum as a biological control agent in combating potato late blight. The study is divided into two main components: Firstly, the study aimed at comprehensively reviewing previous research that uses P. oligandrum in two existing commercial biopreparations and to assess the research to reveal effectiveness of the field-ready products and the biological control agent itself. Secondly, an experimental trial was conducted where the antagonistic effects of P.oligandrum against P. infestans were assessed using detached leaf assay. The thesis aims to bridge the gap between practical applications and experimental findings, highlighting the complexities and promises of deploying biological control agents in agriculture. The review of previous research concerning the efficacy of P.oligandrum biopreparations against potato late blight shows inconsistent results, with much of the variability attributed to the application methods and trial setups, but a variability also across different crops and diseases. However, in a controlled laboratory setting, the application of P. oligandrum was shown to reduce disease severity, although results were not statistically significant. The findings highlight the need for further research to better understand the behaviour and mechanisms of P. oligandrum. Additionally, future studies should focus on optimizing formulations and application methods to enhance its effectiveness in managing potato late blight within an integrated pest management strategy.