Probably depends on where the plane is coming from. Source: me who just returned from Europe last week, no spraying. And have traveled internationally several times in the last few years and also no spraying.

From the link:

"Benefits of entering a voluntary formal arrangement include:

* disinsection methods are undertaken while passengers are not on the aircraft."

Used to see someone wandering down the aisles with spray cans on arrival - but not on the last several trips to Oz.