Hi do I need to check fresh cauliflower and if yes how may I do so?
Cauliflower must be checked for insects infestation, because they usually have insects in the florets. For methods how to check them, here are links to how the Star-k and OU recommend to check them.
As a side point there is cauliflower availible in Eretz Yiasroel with a reliable hechsher for bugs. It wold be recommended to use them and not the fresh ones, as they are often infested.