Level 4 Necromancy (Druid, Sorcerer, Warlock, Wizard)
A creature that you can see within range makes a Constitution saving throw, taking 8d8 Necrotic damage on a failed save or half as much damage on a successful one. A Plant creature automatically fails the save.
Alternatively, target a nonmagical plant that isn’t a creature, such as a tree or shrub. It doesn’t make a save; it simply withers and dies.
Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 4.
Damage by slot level: 4: 8d8, 5: 9d8, 6: 10d8, 7: 11d8, 8: 12d8, 9: 13d8