Blight

Necromantic energy washes over a creature,
draining moisture and vitality from it. The target
makes a Con save, taking 8d8 necrotic damage on
a failure, or half as much on a success. This spell
has no effect on undead or constructs.
If you target a plant creature or magical plant, it
makes the save with disadvantage, and the spell
deals maximum damage to it. Normal plants die
instantly.
At Higher Levels. Each extra spell slot increases
the damage by 1d8.