I am researching around the capabilities and limitations of Killing Curse. Other than humans and animals, is it good for trees and microbes? I am asking this because

  • Trees don't have central consciousness. They can survive from a part. As Killing Curse doesn't destroy the body, it can be problem.

  • Microbes like bacteria are invisible to naked eye which makes it impossible to target them.

Can Killing Curse kill regeneration capability of entire tree? Can Killing Curse be focused on invisible microbes?

Note: I am excluding Virus from microbes as they aren't defined in a boundary of alive or dead.

2 Answers 2


This isn't actually covered in canon. Here's the best guess based on the following facts we know:

  • We know that Killing Curse can be used to kill lower animals (a spider killed by fake-Moody-Barty-Crouch-Jr as a class demonstration on GoF).

    • This means that the curse clearly works on a body, not a soul (as typically only sentient beings are considered as having a soul, and Potterverse never gave any indication it differs in that regard)

    • However, it does NOT damage the body; due to the info we get in HBP when they discuss Vance murder with Prime Minister.

  • We also know that Killing Curse can destroy inanimate objects (whatever stuff Dumbledore used to shield himself in a fight against Voldemort in the Battle of the Minitry in OotP).

Now, we don't know if a tree or microbe would react the way humans/spiders would (dying with no physical damage to the body detectable by Muggles) or the way inanimate objects would (get blown up/destroyed). But it is likely to be one of the two.

  • 1
    I vote for the major explosion.
    – Kaz Wolfe
    Commented Mar 21, 2014 at 2:45
  • 3
    Note that we also have at least two examples of semi-sentient plants: Mandrakes, and the Whomping Willow. It is not at all clear where to draw the line, or if it is even possible to do so, between life forms with souls and those without. (Edit: somehow I feel like Devil's Snare doesn't count, but the Willow does, even though basically both attack people...)
    – BoBTFish
    Commented Mar 21, 2014 at 7:50
  • The microbes for one would almost certainly survive, since a forensic test would quite quickly point to the sudden and complete death of every microbial organism commonly found in human bodies...though that's speculative of how much 'detection' wizards think muggles are capable of.
    – Zibbobz
    Commented Mar 21, 2014 at 14:39

The killing curse's job is to kill, plain and simple. Plant life, though mostly not sentient so far as we know (Dryads anyone?) even by magical standards, would be killed, if not by the curse, then at the very least trees would be set on fire and burn. End of story.

Now Viruses and bacteria are something else entirely. AK was designed as an "opponent killing machine" or rather a "duel winning machine", quick and clean, no spilled guts and foul bodily fluids, no maimed or charred flesh, no crushed bones, or howls of agony. I think there's a chance it might work IF AK hit a vial full of microbes. Intent may be required to kill a specific person, but if the intended target dodges the curse and, say a Hippogriff gets hit instead he'll drop like a stone. AK is for all intents and purposes a magical death ray Hate and malice may be be the required "spark" to light the fuse of that peculiar rocket, but once it's been cast there is no way to cancel or delay the lethal effect because it did not hit the right target. This is not a smart missile whose warhead can be neutralized.

If you want to kill viruses and bacteria it may just be a matter of using the right spell, remember AK was created at a time when admittedly no one knew about microbes and viruses; no microscopes. Though wizards could have discovered it, as a rule they don't seem to apply the scientific method even for magical research and theory. I think wizards would rather use potions, herbs, healing ritual or magically enhanced natural healing. It is interesting though, that the same way there are magical bugs and parasites (e.g., Doxies), there are magical viruses and bacteria causing potentially deadly diseases such a Dragon pox (Abraxas Malfoy / if this disease affects a Dragon it must be very potent) which wizards seem to be vaguely worried about as opposed to common cold (do I smell potential for magical biological warfare?) and other Muggle diseases easily taken care of with a pepper up potion or the like.

My point? There might be a "sanitizing" charm say "Sanito Corpus" or "Expello/Expecto viruses" "Anihilo Microbiens"; pure speculation though.

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