Basic Rules, pg. 219

Blight

4-level Necromancy

Necromantic energy washes over a creature of your choice that you can see within range, draining moisture and vitality from it. The target must make a Constitution saving throw. The target takes 8d8 necrotic damage on a failed save, or half as much damage on a successful one. This spell has no effect on undead or constructs.   If you target a plant creature or a magical plant, it makes the saving throw with disadvantage, and the spell deals maximum damage to it.   If you target a nonmagical plant that isn't a creature, such as a tree or shrub, it doesn't make a saving throw; it simply withers and dies.
At higher levels: When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.