In South Texas, you also need a heartworm preventative year round!
Advantage Multi covers fleas and heartworms (but not ticks). Same with Trifexis. NexGard covers fleas and ticks...but not heartworms. So you're going to need some combination of products.
It's common for people to go with a pill like HeartGuard (or its generic equivalents -- TriHeart Plus, Iverhart, etc.) plus a flea/tick preventative like NexGard or Bravecto.
For mosquitoes, I would spray the yard weekly with Wondercide. We use it in Louisiana, and it helps a lot. It also will kill fleas and ticks out in the yard.
Last edited by Magwart; 11-30-2018 at 02:10 PM.