The Czech Mycological Society note that he died in Prague on Wednesday of natural causes, after a long illness at the age of 86.
"It is a terrible loss," said avid mushroom picker and composer Vaclav Halek, who sets mushrooms to music. "He was a legend and a remarkable personality."
Czechs have been picking and eating mushrooms since the Middle Ages, with an avid passion that sends six out of every 10 Czechs into the forests every year, the society says.
Television news reports often highlight outstanding finds and inform on the twists and turns of the mushroom-picking season.
"It is running in our blood," Halek says. "A Czech equals a mushroom picker. Almost everyone does."
Smotlacha's family has been instrumental in making sure the hobby is safe. Nearly a century ago, his father Frantisek opened the first mushroom clinic to help people determine the edible sorts from the poisonous ones.
Halek recalled that strangers often woke up Smotlacha's mother at midnight to seek expert advice on suspicious finds. He said the Smotlachas efforts to educate, which spread from Prague to smaller towns, have paid off.
"We have had great results in fighting poisonous mushrooms, so people do not eat them," he said. "People here know mushrooms really well. It often surprises me when I chat with strangers and they know 40, 50 types."
Smotlacha followed in his parents' footsteps and dedicated his life to studying and popularising mushrooms. Czech President Vaclav Klaus awarded him for his work in 2005.
Last week, Halek went mushroom hunting with his brother and the duo found 186 magnificent porcini, despite recent news reports that little is growing in the Czech forests.
"Smotlacha would have been happy to know this," Halek said with a nostalgic sigh. "I did not get around to calling him."DPA