COLORADO: The marijuana plant’s worst enemy is so small it’s practically invisible. On weed farms around the country, spider mites attack leaf cells one by one, sucking out chlorophyll like teeny tiny green vampires. If the mites kill enough cells, the whole plant is a goner—an expensive problem considering a single mature marijuana plant is worth as much as $4,000. That’s why more and more, farmers have turned to pesticides. Lots and lots of them.
Unchecked pesticide use has long been the status quo in the anything-goes world of illegal weed farming. But as states legalize marijuana for both recreational and medical use, they’re trying to crack down on the toxic chemicals. In late April, Denver officials quarantined 60,000 plants—worth millions—at a single grower, the latest in a string of punishments for growers using dangerous pesticides. “There was 30 or 60 day period where we were receiving multiple complaints a week” says John Scott, pesticide program manager at the Colorado Department of Agriculture. But exactly what constitutes a dangerous or even illegal pesticide is a tricky, tricky question.
The problem goes back to, you know, a small technicality: Marijuana is still illegal under federal law. That means the Environmental Protection Agency can’t approve any pesticides for use on marijuana. States have been striking out on their own with wildly divergent policies. Twenty-three states have legalized cannabis for recreational or medical use; six have no pesticide regulations at all, while at least another five ban either all pesticides, or all but the most benign—like garlic and rosemary oil.