Can you grab an ant, drag it around in a circular pattern, and thereby create an any circle?
Would this be a viable form of pest control?
Apparently, yes:
(although this is reported in a not-too-reliable source, it looks as though there is a factual basis)
Richard Feynman apparently once tried to do it, but lacked patience:
Not sure how this would be useful as a form of pest control, unless you plan to exhaust all ants into dying in this circle.
Termites will follow lines drawn with BIC brand ballpoint pens since it either mimics or contains a chemical they use as a pheromone. Easier to than dragging around an ant, which may or may not be laying down pheromone
I was going to try this with pine processionary caterpillars last time I was in Spain, but they’re quite dangerous to mess around with
The WIkipedia article on Ant Mills may be useful.
Awww, if you had, we could have added you to this section of the Wikipedia article on the species 
So this appears to be specific to select species of ants and then only to the worker class of the species.
That is cool. From wiki:
Some kinds of ants establish their foraging trails by scent, or pheromones. These are the kinds that can be induced to form a circle or mill. Other ants forage more individually and use sight to navigate. These would not follow other ants in a circle. Of course, it applies only to foraging ants, which are all sterile female workers or soldiers.