POST FALLS - Shut your mouth.

Those smoky-winged ash aphids clouding the air should be telling you to do so.

The winged pests are even more prevalent this October due to the recent sunny days, said Shawn Bennett, an arborist with Grace Tree Service.

"They're more prominent this fall because of the warm, beautiful Indian summer weather that we've been having," Bennett said. "This is what they love."

Bennett said the aphids generally take flight in the afternoons - the warmest part of the day - but said they've been filling the air in the mornings as well.

"This is going to be another rough week with them," he said, referring to the predicted sunny days ahead. "But a frost or rain will knock them down. They should be done in another two weeks."

Until then, folks such as Post Falls' Jerry Thomas, who walked his dog, Razor, at Kiwanis Park on Monday, will have to tolerate the pests.

"They get on your clothes, in your eyes and in your hair, so luckily I don't have much of that (hair)," Thomas said. "They make it so that it's not near as pleasant to walk your dog - that's for sure."

Bennett said he has taken in about a dozen of the bugs in his intake valves while making his fall rounds and exercising.

"If you go bike riding, you may want to check your teeth before you smile," he said.

Bennett said the aphids, which don't bite, are more of a nuisance than a destructive insect.

"They don't cause a lot of damage to crops, so unfortunately not a lot of money has been put toward research on them," he said.

Bennett said the aphids congregate on the trunks of green ash trees. The alternate host is Douglas fir trees.

"They can cause the leaves of ash trees to curl and cause yellowing to young Douglas firs, but they don't do much more than stress trees," Bennett said.

The aphids develop wings in the fall and return to the ash trees to lay eggs which hatch in the spring.

Controlling the pests is difficult, if not impossible, because a neighborhood may have many ash or fir trees.

"Honestly, treating them will have little effect," Bennett said.

Residents who are really bugged about them may still wish to do what they can by spraying the trunk of the trees with water in the early morning or late evening when the aphids are dormant. Non-toxic dormant oils are also available.

"The oils coat the eggs and in the spring, when the sun comes out, it cooks them," he said.

Bennett said, as difficult as it may seem, the aphids are a fall tradition people generally just have to accept.

"They're just like geese flying south," he said. "When we see them, we know that autumn is in full swing."