August 6th, 2015 – The Oregon Department of Agriculture is warning marijuana growers to stop 
using illegal pesticides, while the state scrambles to put together a list of acceptable chemicals.
The federal government puts pesticides through tests that determine in what context a chemical may be used in agriculture and how much may be used. Those accepted uses are then listed on the label of the pesticide.
However, because cannabis is an illegal substance according to federal laws, there are no approved pesticides to use in marijuana cultivation. So, while many growers use pesticides, the application is technically against the law.
“It is important to note, pesticide applications that do not follow the pesticide product label pose risks to public health and safety and are a violation of state and federal law. THE LABEL IS THE LAW,” says a letter being sent to every permitted marijuana grower in Oregon.
Pesticide residues can often be found on cannabis products that claim to be pesticide-free. Third-parties in Oregon have several marijuana products and found that almost all of them tested positive for pesticide traces.
A state task force of people involved in the industry, the Oregon Liquor Control Commission, ODA and the Oregon Health Authority met Wednesday to figure out how to regulate pesticide use and testing.
They are still debating which pesticides should be allowed for use on marijuana and how to test for those chemicals without bogging down growers and processors in fees. Because the legal recreational industry is so new — possession and growing of marijuana for adults 21 and over became legal July 1 — recreational marijuana businesses are adjusting to the regulations that now govern what was largely a black market industry for years.
Lab technicians who test products before they go to store shelves said that most marijuana leaves, flowers, concentrates and extracts are turning up with some pesticides on them, whether the grower applied them or were contaminated from other sources.
Lisa Hanson, deputy director at ODA, said that her staff, along with OLCC and the health department are putting together a list of advisory pesticides, but in the meantime, growers may be in the safe zone using chemicals that Environmental Protection Agency — which oversees pesticide permitting — that have very low toxicity, such as garlic oil.