Strawberry diseases can be tested from plants and soil In strawberry cultivation, crop damage can be caused by plant diseases, such as crown rot and red stele. Nowadays, however, plants can be tested for diseases at the time of purchase, and it is also possible to detect diseases in a soil sample taken from the farm. The development and selection of new disease-resistant varieties also increases the yield. TEXT MARIANNE MUSTONEN PHOTOS HARRI KOKKO AND RAIJA TÖRRÖNEN
“OVER THE last few years, strawberry plant deliver-
Red stele pathogen can’t be removed from the
ies have had a number of poor plants in them, and
soil, either, and no biocides against these diseases
strawberry farmers haven’t been able to identify the
exist. This is why it is important to study and develop
disease. Yields have been poor and there have also
increasingly disease-resistant varieties of strawberry.
been incidents of total crop failure,” says Researcher
“We study the resistance of different varieties by
Harri Kokko from the Department of Environmental
pot experiments and by inoculating detached leaflets
and Biological Sciences.
in the laboratory. In pot experiments, we expose
“In the worst case scenario, farmers can lose half of their plants right at the beginning, with the rest dying in a couple of years’ time.” Strawberry plants are commonly imported into Finland from the Netherlands and Poland, among other places, and 15–20 million plants are planted every year. Red stele has been discovered in plants,
strawberry varieties to pathogenic spores and study their symptoms,” Researcher Anna Toljamo explains. “We produce clean runner material for our experiments, as infected material naturally can’t be used.” Although plant diseases are widespread, the researchers are confident that a solution will be found. “Varieties that are resistant to red stele have al-
and many farms have also been struggling with
ready been developed, but these haven’t been studied
crown rot. Furthermore, last summer’s cold and
with races of red stele that are prevalent in Finland.”
damp weather worsened the disease situation.
“Moreover, full resistance to crown rot hasn’t been achieved yet,” Researcher Mustafa Munawar says.
BY TESTING PLANTS FOR DISEASES in their country of origin, it could be ensured that only healthy
IT IS IMPORTANT for the researchers to be able to
plant material ends up on farms.
help farmers in their work. Curiosity drives them
“Our research has been ongoing for a year now. We are testing plants for diseases and helping farmers identify them. We’ve got some guidance for this work from the US, and we’re the only ones doing this in Finland.” A novel testing method makes it possible to
to uncover the genetic mechanisms behind plant diseases. “Plant diseases are a major problem, and we need to get them under control,” Toljamo says. “Strawberry farmers need expert help, but this is not something we make commercially available
identify diseases without having to isolate the plant’s
through the university. Luckily, farmers can make
DNA. The testing device is small and portable, and
use of our research findings,” says Munawar, who is
it can be used out in the field. Furthermore, the test
mainly interested in innovative molecular biology
results are ready within the hour.
There are still some reservations among farmers
“It’s great that nowadays we can do research all
about the new testing method, because there are so
year round, thanks to our LED-illuminated rooms
many different diseases. Moreover, it is possible farm-
and growth chambers. We are able to work on a
ers haven’t fully grasped the competitive advantage
continuous basis instead of having to wait for the
they could gain by testing their plants beforehand yet.
growing season,” Kokko says.
“We are also developing a method that enables the identification of hidden pathogens in the soil,” Kokko says.
OOSPORES OF RED STELE survive in soil for 15–20 years and, in the event of heavy rain and flooding, they travel in the soil and spread disease. Planting strawberry plants is expensive, and this is why it makes sense to test the soil in advance.
24 UEF BULLETIN 2018
Plant diseases are a major problem, and we need to get them under control.”