Simply swarm the blowhog. The Pikmin should be called back when the Blowhog begins to buck. If the Pikmin are thrown off, then they usually lose their flowers, and non-whites will have trouble with the poison jet. Calling the Pikmin with the whistle will save them if they get in contact with the gas. As always, a considerable amount of Purple Pikmin will kill the Blowhog if thrown onto it. You can also leave some whites alone to face the Smoky Blowhog without harm, but steer the Blowhog away from any potential danger.