Simply throw Pikmin (red ones are best, because of their high attack power) onto its face. Call them back to you if the Bulblax is about to eat them.
You can find them in the Hole of Heroes and the Bulblax Kingdom.
If you mean the Emperor Bulblax, he can be a toughie. I once saw a guy on YouTube beat him with not a single Pikmin death! In fact, he beat the whole game in 9 days with out 1 Pikmin dying! Anyway, use mostly Red Pikmin, the more with flowers the better. Also use Bomb-rocks. I lost 198 Pikmin on this fight, hopefully you can do better!
In pikmin 1, you must get to the Forest of Hope, then go right, destroy the wall at the end then approach the onion in the ground, and in pikmin 2, you need to get to the Perplexing Pool, then go left on the white trail, then go right at the end, then take your red pikmin and white pikmin and kill the fiery Bulblax, then destroy the poison dirt wall, then whistle the yellow pikmin off the tree.
The Prototype Detector (the ship's name for a Love Tester), which gives you the Treasure Gauge, is found in the Empress Bulblax at the bottom of the Hole of Beasts.
After collecting the 2nd half of the globe treasure found in the Awakening Wood, go to the Perplexing Pool. Walk forward to find a cutscene showing the Yellow Pikmin. Then continue to walk past the Yellow Wollywog, to a set of scales. Throw all but 1 pikmin up there. Throw the last pikmin, while standing on the lower scale, on to the higher one to be lifted up. Once there, kill the Fiery Bulblax, and break down the poison gate. Walk to the pikmin and whistle to them and Yellow Pikmin are all yours.
You can't. Your only choice is to avoid the Waterwraith and carefully collect treasure. On the final sublevel, you can get purple Pikmin, which allow you to defeat the Waterwraith.
Simply throw Pikmin onto its head. Yellow Pikmin are the best for this, since they can be thrown higher. It also helps to use Ultra-Spicy and/or Ultra-Bitter Spray.
Since the Goolix is made mostly of water, blue Pikmin are best to fight it. Throw them on the smaller blue nucleus to damage it. You can also damage the Goolix by throwing Pikmin on the yellow nucleus, but this will make it throw all attacking Pikmin off.
Emergence Cave, Subterranean Complex, Frontier Cavern, Hole of Beasts, Bulblax Kingdom, Snagret Hole, Citadel of Spiders, Glutton's Kitchen, Shower Room, Submerged Castle, and Cavern of Chaos.
No there is not a Pikmin that will give you more or additional Pikmin.
When it makes some poisonous gas, take out the pikmin because if you do not, they will attack you. After some time, he will get defenseless with his head on the floor, and that is when you attack him. Usually you have to follow him and trip him, though. View the link below for a walkthrough of the game.
No. White Pikmin made their first appearance in Pikmin 2.