Docent/Associate Professor in plant pathology.

Working for many years in the subject area: Plant interactions with beneficial bacteria and fungi (including mycorrhizal) and pathogens in order to utilise these interactions for stimulation of plant growth and biological control of plant pathogens.

Stimulation of plant growth by a biocontrol organism in potato in the field. Control to the left.

Plant health is influenced by its microbial residents. Our studies focus on untapped potential of naturally occurring bacteria and fungi particularly those living with plants. These can be used to improve plant health by improving emergence, growth and yield as a result of biological control and increased plant vitality in soils naturally infested with pathogens. Biological control is, in general, use of a living beneficial organism selected by human beings to control a particular pathogen. This chosen organism might be a hyperparasite or an antagonist or biocidal. It should be harmless to the environment and the target crop.  

Given the recurring problems with poor growth and crop establishment, pathogen resistance to chemicals, lack of effective means to control soil borne pathogens and environmental hazards of chemicals, biological control by both introduced agents and indigenous microbial antagonists is crucial for crop safety. Successful use of biological control requires a greater understanding of the biology of both the pathogen and its antagonist as the results of using biological control are often not dramatic as of chemicals. Understanding of multifarious interactions taking place between the plants and pathogens with their surrounding micro-organisms will provide us the knowledge for successful sustainable management of agricultural systems.

Ongoing projects:

Biological control of soil borne diseases in potatoes

Soil-borne diseases are of economic importance in the Swedish potato cultivation. Yield losses due to fungal pathogens causing various scurf diseases; Rhizoctonia solani, Spongospora subterranea and Helminthosporium solani are important since they reduce product quality and large quantities may be discarded. The project aims at 1.) studying effect of bacterial antagonists, composted herbs and arbuscular mycorrhizal fungi for control of scurf under field- and greenhouse condition using naturally infested soils, and 2) effect on pathogen communities on tuber surface. Through the use of microbial synergy, we intend to ensure the reliability of the best treatments and increase crop security.

Composted herbs to control late blight in potatoes

Potato late blight causes considerable damage in potato. The aim is to find environmentally friendly methods to control late blight in organic potato cultivation. The guiding hypothesis is that treatment with specific compost teas can be used for reducing the disease and that inhibition of late blight is due to their antagonistic microbial communities. The planned investigations, include testing of various compost teas for their direct effect on Phytophthora infestans in vitro, on late blight on foliage and rot in the tubers and studying the composition of the microbial communities of compost teas. The project is expected to identify plant species with potential for effective control of late blight and brown rot in practical farming.

In vitro suppression of Phytophthora infestans by an antagonistic bacterium. Control to the left.

Co-Supervising

Xuan Do Thi (Ph D student): Microbial communities in tropical crop systems -  emphasis on rice and rambutan
Saraswoti Neupane (Ph D student): Interactions between fungal pathogens and bacterial antagonists - their influence on oilseed rape emergence and early establishment
Srivathsa Nallan (Ph D student): Exploiting soil microbial activity to enhance nutrient acquisition and sustainable pathogen control in strawberries

Funding from

• National Board of Agriculture
• Ekhaga Stiftelsen
• Department of Forest Mycology and Pathology