As per this DnD 5E Blight Spell the necromatic energy will wash over a creature which is on your choice that too you can see within a range, the draining moisture and also vitality from it. But in this dnd spell the target should make a constitution saving throw, the target would normally take 8d8 necrotic damage on a failed save, or else half as much damage on a successful one. Basically this spell does not have any type of effect on undead or constructs.
Suppose, whenever if you target a plant creature or the magical plant then it will make the saving throw with a disadvantage and even the spell deals maximum damage to it.
But when you target a nonmagical plant which is not a creature, like a tree or shrub, and it does not make saving throw, it simply withers and then it dies.
At Higher Levels:
So, whenever you cast this d&d 5e blight spell by using the spell slot of 5th level or more than the 5th level, the damage would increase by 1d8 for each slot level above the 4th.
Attributes Of Blight
|Casting Time||1 action|
|Classes||Druid, Sorcerer, Warlock, Wizard|
|Higher Spell Slot Desc||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.|
|Higher Spell Slot Dice||1|
|Higher Spell Slot Die||d8|
|Target||A creature of your choice that you can see within range|