Re those big, cultivated stands of cannabis you sometimes hear about DEA agents discovering in the middle of the Ozarks & other remote wooded locations.
Does marijuana grown outdoors have any natural pests in the US?
Racoons will dig them up out of spite if plants are in their territory. Deer will eat the plants maybe up until around the time they sprout. When the plants are real small big slugs have been known to take them out. As they get bigger there is a bug that lays an egg in the stem, as the larva matures the stem usually breaks at that point and yuo loose the most, um, budaceous part of the plant. There are other bugs too among them, white flys. Pyrethrum works for those.
But, really, nothing that will take out an entire crop the size of which you are thinking about.
This just, of course, is just what I heard, mind you 
Dunno about the US, but here in NZ the possums will eat 'em branch, leaf and shoot. So they tell me.
Oh, and Dopers, of course.
Hemp Diseases and Pests: Management and Biological Control should tell you what you want to know.
There’s also this article:
I’m just suggesting that “out of spite” is a bit of anthropomorphizing. It may seem like that to you, but a better explanation might be that they stake out a territory and try to keep it free of animal or plant intruders. You might, ahem, feel that the animals are spiteful. I’m guessing many of us can relate under the circumstances. Just guessing, of course. xo C.
I would go much further.
What is the connection between “plant and animal intruders”? Though I can’t pretend to see into the raccon mind, I do not believe that they create the same mental categories that we do, which might lead them to class plants and animals together as living organisms and intruders.
I have never heard anything that indicates that raccoons attack invading foreign plants (or insect or fish etc.) to any great effect, if at all. There has no shortage of “foreign species” where this effect might have been recorded, and there has been --and is, ongoing-- extensive study of the spread of such plants and animals.
Instead, I would argue that raccoons recognize human intruders (which is well documented) and have come to associate these plants with human incursions. It’s quite possible that just the human stink is enough, but my own experiences with raccoons suggest that they can conclude these plants are the product of human activity and are, as a lawyer might say, an “attractive nuisance”.
A raccoon cal that chews down “human stink” plants in its domain, and was rewarded by humands going elsewhere, would continue the behavior for at least a generation (recorded as up to 16 years in the wild). This is well within the range of known raccoon behavior.
(I wouldn’t be surprised if their conceptions were even more sophisticated. They are quite clever. I wouldn’t even be surprised to see it passed down a generation by unnoticed “attacks” on other objects accidentally left by humans. While hiking, I have seen possible toothmarks on inedible ‘human’ items)
Are you saying that an NZ[sup]1[/sup] possum eats**,** roots and leaves?
I don’t know why everyone gets so cautious when answering questions on this subject. Cecil answered a similar question long ago: My marijuana plants have bugs! What do I do?
[sup]1[/sup] Actually they are imports from Australia and not the same species as US possums.