Since the grubs live in and thrive on decaying matter, turn over any piles of mulch, compost, leaf litter, grass clippings, and animal manure frequently in spring.
Leaving a juicy, dripping fig (or any other fruit) on a branch is just an invitation for clusters of figeater beetles to descend on your tree and feed all day, living up to their name.
Remember that any barrier will also prevent pollinators from reaching the flowers, so place the covering just before the fruits start to mature.
To eliminate fig beetles the old-fashioned way, hand-pick each one and drop it into a bucket of soapy water. Dish soap works fine for this, and it doesn’t take much to kill them.
There are many variations of homemade bottle traps, but the easiest one to make only requires a soda bottle and some bait.