Grass and Bug types: weaknesses, resistances and Pokémon
Grass and Bug Pokémon take quadruple damage from Fire and Flying moves, take double damage from Ice, Poison, Bug and Rock moves and resist Grass, Ground, Water, Electric and Fighting moves.
The balance is even: 6 weaknesses and 5 resistances or immunities.
Grass moves are super effective against Water, Ground and Rock and not very effective against Fire, Grass, Poison, Flying, Bug, Dragon and Steel. Bug moves are super effective against Grass, Psychic and Dark and not very effective against Fire, Fighting, Poison, Flying, Ghost, Steel and Fairy.
To beat these Pokémon, your best pick is Fire and Flying moves. Avoid Grass, Ground, Water and Electric moves, which deal little or no damage.
There are 6 Pokémon with this combination, such as Paras, Parasect, Wormadam and Sewaddle.