Of course, a Grass type Pokémon can defeat a Bug type Pokémon.
But Grass type moves are "Not very effective" against Bug type Pokémon, meaning the power of the Grass type move is halved.
BuG TyPe CaN dEfEaT a DaRk TyPe
Grass type Pokémon are weak to Fire, Flying, Ice, Bug and Poison. Ground types are weak to Water, Ice and Grass. So both types are weak to Ice.
Leavanny is a Grass and Bug type pokemon.
Wormadam is a Bug and Grass type pokemon.
Swadloon is a Grass and Bug type pokemon.
Catterpie, Roselia, Scyther and many many more grass type Pokemon can learn bug type moves.
Parasect is the dual Bug/Grass-type Pokemon.
Paras is the dual Bug/Grass-type Pokemon.
No, it is a Grass/Bug type.
Fire types are good against Steel,Ice,Bug,and Grass Pokemon.
Bug-type Pokemon are strong against Grass, Fighting, and Ground-type moves.
Grass-type Pokemon are weak against Fire, Flying, Poison, Ice, and Bug-type attacks.