The Zerg late-game is probably one of the toughest scenarios to play against. There’s nothing quite like that feeling when you march your army towards your Zerg opponent’s base and your leading stalker is struck by a flying broodling.
As someone who has fought Zerg in the bronze league, the key lies in switching from colossus tech to templar tech as soon as possible. Basically, if you see corruptors during the mid-game, that is the cue for you to switch to templar. Don’t forget to research psionic storm, of course.
If you are lucky and you engage in a head-to-head battle against a broodlord (plus roach/ling/infestor) army, preferably you’d want to have a good mix of stalkers, zealots, archons, and of course, high templars. The quickest way you can defeat that zerg swarm is to storm the be-jesus out of the broodlords and the ground army underneath them, and proceed to blink the stalkers underneath them and take them out one by one.
Now, the mutalisk is a different story. I am one of many who often fall victim to the dangerous muta-ling strategy because the mutalisk harass is too annoying and frustrating to be up against. While the bronze level muta harass is easy to deflect, anything higher than bronze starts to get a bit tougher. I’m in no position to provide any detailed tips as to how to deflect mutas, suffice to say that I generally rely on a combination of stalkers and cannons to protect my base while massing up an army to kill the opponent. This often doesn’t work.
For a better way to defend against mutas, check out Day9’s daily on LiquidHero’s PvZ play, where he stations high templars at his main and expansions and storm mutas as they come in to harass.