Pot puzzle: What’s safe level of pesticide?

Associated Press

DENVER

Microscopic bugs and mildew can destroy a marijuana operation faster than any police raid. And because the crop has been illegal for so long, neither growers nor scientists have any reliable research to help fight the infestations.

As legal marijuana moves from basements and backwoods to warehouses and commercial fields, the mold and spider mites that once ruined only a few plants at a time can now quickly create a multimillion-dollar crisis for growers. Some are turning to industrial-strength chemicals, raising concerns about safety.

Pesticides and herbicides are regulated by the federal government, which still regards almost all marijuana as an illicit crop, so there’s no road map to help pot farmers. Chemists and horticulturalists can’t offer much assistance, either. They sometimes disagree about how to combat the problem, largely because the plant is used in many different ways – smoked, eaten and sometimes rubbed on the skin.

“We have an industry that’s been illegal for so many years that there’s no research. There’s no guidelines. There’s nothing,” said Frank Conrad, lab director for Colorado Green Lab, a pot-testing lab in Denver.

In states that regulate marijuana, officials are just starting to draft rules governing safe levels of chemicals. So far, there have been no reports of any human illness traced to chemicals used on marijuana, but worries persist.

The U.S. Environmental Protection Agency, which decides which pesticides can be used on which crops, told Colorado and Washington authorities that they could apply to have some cannabis-related chemicals approved through what’s called a “special local need registration.” But that process could take years.