Sonoma County grape growers have been warned to watch for arsonists in their vineyards after a suspicious fire near MacMurray Ranch in Healdsburg on Friday afternoon.

“It has been brought to our attention that an arsonist was seen along Westside Road with a flare. When the grape grower arrived and saw smoke, the arsonist fled and unfortunately was not caught,” said Karissa Kruse, president of Sonoma County winegrowers in an alert sent to growers.

Forestville firefighters said they kept the 3:20 p.m. fire under a half acre. They said the cause of the fire was being investigated.

Neighbors said a tasting room employee glanced out the window and saw a column of smoke rising. He immediately called the fire department, closed the tasting room and rushed to help the firefight.

Kruse, who lost her own home in Fountaingrove to the fire, said, “It is with a heavy heart that I report this information.”