PORTSMOUTH, R.I. — A tiny spider mite is all it could take to cripple Seth Bock’s business.

Bock grows marijuana, legally, for a living, and the peril presented by just one small insect illustrates how difficult it can be to establish a thriving dispensary.

His is one of three medical marijuana dispensaries in Rhode Island, and his experience provides vital lessons for companies in Massachusetts that have won licenses to grow and sell marijuana. The first is expected to open in April.

For marijuana dispensaries, it’s never as easy as sticking a few seeds in the ground and watching the plants, and the profits, grow. “There are so many moving parts to this business,” Bock said.

Missouri is high on my list of states that could legalize marijuana by the end of 2016. Missouri has the strongest campaign team I have ever seen (Show-Me Cannabis), and I always say that if they can legalize in Missouri, they will prove that any state can do the same. Unlike Western and Northeastern states, where views towards cannabis are generally more liberal, Missouri is in the heart of America where reefer madness is much more prevalent.

An undated photo of Larry and Rhonda Harvey(Photo: Courtesy of Larry Harvey)

SPOKANE, Wash. — Federal prosecutors are trying to persuade a jury that a cancer-stricken man and his family were illegally growing and distributing marijuana in the forest outside their northeastern Washington home despite claims by the "Kettle Falls Five" that they were instead raising legal medical cannabis for their personal use.

A user prepares to roll a marijuana cigarette on the first day of legal possession of marijuana for recreational purposes in the District of Colombia on Thursday. Alex Brandon/AP hide caption

itoggle caption Alex Brandon/AP

Nearly two-thirds of Millennials who identify as Republican support legalizing marijuana, while almost half of older GOP Gen-Xers do, according to a recently released Pew survey that could be an indicator of where the debate is heading.

BOISE, Idaho

Ten-year-old Alexis Carey has a rare but intractable form of epilepsy, Dravet Syndrome. The genetic disease causes severe and multiple seizures, which often leave parents guessing if the terror of watching their child seize up will pass or turn fatal.

Her Boise, Idaho, family learned that oil extracted from marijuana had helped other children and wanted to see if it would help Alexis too.

"Parent to parent, when you're in a small community and 10 people that you know are all having success, that's no longer anecdotal," Clare Carey, her mother, said. "That's hope."

Colorado has released its first annual report on the status of the marijuana market a year after legalization in the state. It shows a growing industry that has sold nearly 75 tons of cannabis flower and almost 50 million units of pot edibles.

A year after the first licensed marijuana retail stores opened in Colorado, the Marijuana Enforcement Division says the state has sold nearly $700 million of medical and recreational marijuana in 2014. More than half of that, or $386 million, was spent on medical marijuana while $313 million accounted for recreational use.

VANCOUVER -- The free-for-all era of Canada's commercial medical marijuana industry is over as a new crop of growers try to woo scarce investment dollars in an increasingly competitive business, observers say.

Boris Ziger, CEO of Matica Enterprises Inc., said the short-lived days of unbridled growth ended soon after last year's change in federal regulations that shifted medical-marijuana production to commercial enterprises from patients growing their own pot.

He said the stock market went "absolutely crazy" in the spring of 2014 as various companies began branding themselves as pot producers in hopes of cashing in on what was really "irrational exuberance you hear about in business school."

Syracuse, N.Y. - The first U.S. public company allowed to raise money on the stock market to produce and sell medical marijuana wants to grow pot in Central New York.

Terra Tech Corp., of Irvine, Calif., plans to apply for a state license to cultivate and dispense medical marijuana in New York, said Derek Peterson, the company's CEO.

"We're looking at Central New York for cultivation," Peterson said. "If you want a retail footprint around the state, you want cultivation and production centrally located adjacent to major arteries to provide access to all the retail locations."

The company has not picked a Central New York location yet, he said. Peterson said dispensaries would be scattered around the state in places such as Ithaca, Albany, Manhattan and Brooklyn.

Tribal leaders, lawyers and marijuana-industry representatives gathered in Tulalip for the nation’s first tribal marijuana conference, an event that served as much as a policy debate on the merits of legalization as it did an educational session.

Colorado's marijuana industry is producing a lot less than it could, according to a state report released Friday.

Although state laws limit how many plants a business can cultivate, the monthly average for medical marijuana businesses last year ranged from a third to about half of what they could have produced, according to the annual update released Friday by the marijuana enforcement division of the Department of Revenue. The division estimates retail cultivation averaged 40 percent or less of the production limit.

Other highlights of the report:

-- Of Colorado's 312 cities and towns, 228 prohibit medical and retail licenses. Still, the places that allow sales include the state's population centers, among them Denver, the capital.