Staghorn Fern Help!

Hi all. My staghorn is infested with some kind of bug and I don’t know what the to do! Whatever the bug is, it leaves a mealy type substance and spider web type stuff in between the leaves. I’ve used copious amounts of maverick without any success and don’t know what to try next?? Due to the staghorn being SO big it isn’t an option to soak it in water. Thanks in advance for any suggestions.