Colorado is acting to stem a growing black market for marijuana since the state legalized recreational use in 2012. Oregon lawmakers should consider more direct action as well.

Colorado earmarked $6 million in marijuana tax revenue to reimburse police departments for crackdowns on illegal growers. Oregon allocates 20 percent of pot taxes to local law enforcement, but doesn't specify how the money is spent.

There is no question Oregon marijuana ends up in states where it is still illegal, commanding many times the price growers get here. An Oregon State Police study obtained by The Oregonian in March found Oregon marijuana production outstrips demand, creating a surplus worth millions in other states.

Medford and Grants Pass are among the cities with the greatest connection to black-market destinations across the country.

A study by Whitney Economics estimated illegal sales will account for about 35 percent of the Oregon market this year, down from 80 percent in 2014. That shows legalization is slowing illegal exports, but there is still a long way to go.

One obstacle is the role of the Oregon Liquor Control Commission, which regulates the recreational market but has no authority to go after illegal growers. The OLCC investigates illegal liquor sales, but the Legislature did not give it enforcement power under the marijuana law.

Eventually, the illicit market will dwindle as more states opt for legalization. Meanwhile, recreational and medical growers who are playing by the book have every reason to support efforts to weed out black-market operators.