The disease, caused by the fungus Valdensinia heterodoxa, was last seen in Estonia in 1980, with one trace found in DNA soil samples 10 years ago.

The disease is not hazardous to humans, but renders blueberries inedible.

An unusually large amount of fungus causing blueberry leaf spot has been found in Finnish forests this summer, so far destroying around a fifth of the crop, with blueberry leaves visibly spotted, the berries dried out.

The rainy spring and early summer, which created favorable conditions for the spread of fungal diseases, are thought to be the main culprit.

Kaire Loit, lecturer of phytopathology at the Estonian University of Life Sciences (Maaülikool) said the fungus had likely been present in Finland prior to the recent discoveries. "I think this fungus had been there long before this discovery. When we start investigating something, the more we study, the more we find. Likely in the case of the Finns as well, someone happened to take a closer look at these blueberries," Loit told "Aktuaalne kaamera.!

Meanwhile in northern Estonia, the first early-ripening blueberries are already ready to eat. No spots have been seen on the leaves, while according to the Agriculture and Food Board (PTA), no blueberry fungal disease has been detected in Estonia so far.

Piret van der Sman, head of the Maaelu teadmuskeskus Saku laboratory, said: "Up to now, no samples with such symptoms have reached our lab, so we cannot say whether it is in Estonia or not. If people find plants with symptoms, they should of course bring them to the lab and identify what disease it is. As the situation is right now, we can say that to our knowledge, this disease has not yet been found in Estonia."

It may not stay the same way, however.

"In general, we do have quite a similar climate to Finland and blueberries grow in our forests too. There is a high probability that it will reach us as well, and we also cannot rule out that it is already here, and perhaps in Finland this year the weather conditions have been so favorable that the symptoms have emerged and become so pronounced," Sman said.

One berry foraging enthusiast, Liisa Kallari, told ERR blueberry crop has been pretty good this year and the berries are beautiful, although they ripened later than usual.

"Really we looked around and, compared with previous years, the blueberries are very sweet and sizeable, and we certainly don't know anything about a fungal disease. The berries are beautiful. I would actually say that in those places I go to, everything is blue," Kallari said.

Valdensinia heterodoxa was first observed in Estonia in 1935, in the southeast of the country.

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