The only way to get Beenades is to defeat Queen Bee. She can drop them naturally or you can craft them from the Bees Wax she drops by mixing them with Grenades(which can be purchased from the Demolitionist).
If you need to defeat Queen Bee, find a hive in the jungle and somewhat clear out the hive and make a platform arena big enough so you can move around and dodge her effectively. Use the honey to your advantage for extra regeneration. Be sure to put Heart Laterns and Campfires to increase regen further, and a Regeneration potion is a plus.
Her pattern is simple(assuming that you are playing Normal): She starts out with a series of charges. These horizontally swipe through the screen in an attempt to hit you. This travels reasonably fast, but isn't too jarring to dodge as long as you pay attention. These can be dodged with a simple jump, but having accessories that give extra vertical mobility(like a double jump bottle or the ballon) will assist in dodging it further. Use the minimap to your advantage here, her location pops up on it and helps you in timing your jumps, especially in the dark Underground Jungle.
After that, she enters a random pattern of shooting stingers or shooting out Bees. She shoots stingers reasonably fast, similar to Hornets. These can be tough to dodge, but maintaining a fast horizontal movement should suffice in Normal mode(use Lighting Boots or Hermes Boots. Grappling and detaching repeatedly in a timed succession can also let you build speed, though it's tough to master). She also tends to swipe down at you whilst shooting you in an effort to deal contact damage. Again, a simple jump or fast horizontal speed should avoid that. She will also try to switch to shooting out Bees. These chase you similarly to how the bees from the Hive traps chase you. However, they boast a low health, so keep putting pressure on with a fast firing weapon like a Minishark or a high pierce weapon like Vilethorn or a bow with Jester Arrows in case they form crowds. If the bees surround you, use a sword to shake them off. After she is done cycling through her "ranged" pattern, she will do another series of charges and then it repeats.
Weapons that I'd recommend for the battle: Minishark(high DPS), Space Gun(even better with Meteor Armor, can be used for all phases of the battle, can take out the bees and apply a steady stream of DPS), Water Bolt(better for when she is in the ranged phase), and a strong bow like the Tendon/Shadow Bow with a strong arrow type like Jester or Frostburn(Isn't the best option, but still a strong option.) There are many other weapon options available, feel free to look on the
wiki.
You should have at least Gold armor if you are trying to challenge the oversized bee, but considering that you are able to survive the underworld, armor and accessories shouldn't be an issue. Just make sure you have enough mobility to dodge her attacks and have enough defence to suit your needs. If needed, reforging accesories to have defense can help tremendously against pre-hardmode bosses, but can get a little expensive with certain accessories.
Hope this helps! And as I said before, feel free to ask for more tips! :D
