There actually are many different kinds of parasites controlling their hosts to behave in a certain way that aids the parasite.
The Ophiocordyceps is a fungus whose spores infect ants living up in trees. They let the ant climb down the tree and clench its teeth in leaves of low growing plants before they kill the host to spread the spores because the fungus can only grow and infect other ants in the wet areas close to the ground.
The Toxoplasma gondii is a protozoan that proliferates in feline intestines. After defecation they infect other animals and in some, like rats, they are able to induce chemicals into the host's brain, which deactivates their natural fear of the smell of cats urine and replaces it with attraction so the rat is more likely to get eaten by another cat.
The wasp Hymenoepimecis argyraphaga lays its larvae in spiders, who then use chemicals to control the spider to spin a web as a support for the larvae's cocoon before it kills and eats the spider.
Hairworms infect crickets and use chemicals to alter the host's behaviour to jump into water and drown because the worm can only reproduce in an aquatic habitat.
There are many more examples of mind alteration in animality so yes, I'd say for the right reasons it would be absolutely plausible for one intelligent species to mind control another one (not even necessarily a less intelligent one) to serve certain purposes aiding the controller, who cannot do the work on his own, or (as we are talking about intelligent life forms) does not want to do the work on his own. The latter case is not plausible in your case, as you mentioned the controllers to not be technically advanced, so I'd assume their controlling behaviour developed evolutionarily and thus needs a proper reason.