Vasari is really cheesy, I'm having trouble at the moment dealing with Vasari that will rush to build a starbase in your home planet, and using the carrier and health regen it is almost impossible to destroy before it gets built.
Is there anything early game that can stop them from getting built or blow them up?
You're talking about when people use that strategy against you in the really cramped online games, like 5v5?
To defend against it, it really depends on what race you are. If you're TEC, you're in luck: in those sorts of games, you should already be researching LRM frigates ASAP and invest in almost nothing else if you're against Vasari (except for colonizing that asteroid right next to your homeworld). You should be able to build 20 or 30 LRM frigates very soon into the game - if you use those to focus-fire on enemy Orkuluses that start building on your planet, you should be able to destroy it relatively quickly. Combine with a carrier cap with fighters to maximize firepower. (Make sure to keep building LRM as soon as you get the funds)
Remember, you don't have to destroy it before it finishes to come out on top - a starbase costs a whole lot, so even if you've lost a single batch of LRM frigates to the starbase's weapons before you manage to kill it, you may still have the advantage.
If you're Advent... build a ton of Disciples ASAP in similar fashion and hope you have enough numbers to overwhelm the starbase. (To be honest, if you're Advent and are facing a skilled Vasari enemy somewhat close by, you're pretty much out of luck anyway)
If you're Vasari... build a ton of Assailants ASAP, similarly, and focus fire on the Orkulus if it starts building. It shouldn't live for long, especially if you have the first two Phase Missile weapon upgrades.
