How a marijuana 'crop plague' could force growers to change their practices

Updated Feb. 13 at 5:03 p.m.

While the state’s marijuana business continues to boom, cannabis growers in Massachusetts — already facing tough business setbacks in a competitive and volatile market — are scrambling to ward off a rapidly spreading and highly infectious crop disease, one with the power to wipe out entire companies.

“It’s like the tenth plague for the cannabis industry,” said Peter Grinspoon, a medical cannabis specialist at Massachusetts General Hospital. “The margins are drying up for anybody growing cannabis. They need this like they need a hole in the head. It’s a nightmare.”

Hop latent viroid, a plant-specific pathogenic RNA, sucks the THC potency out of cannabis plants, degrading the quality and resulting in significantly smaller yields. It's sometimes referred to as "dudding disease."

The pathogen has already blighted California’s cannabis crops, resulting in $4 billion annual losses, according to cannabis genetics research company Dark Heart Industries. The pathogen has no known effect on human health, though Grinspoon and other experts say very little research exists.

Grinspoon says the disease is causing a “total evolution” in the cannabis industry, as manufacturers are forced to adopt more stringent measures to combat it. Their prevention efforts include more rigorous sanitation in grow facilities, regular lab testing, and sourcing plants from pre-tested seed or local stock — steps that come at a cost.

“If you were cutting corners, I’m sure you have stopped cutting them by now,” Grinspoon said. “It’s not in your economic interests to cut corners when something like this is spreading from crop to crop.”

Where cost-cutting may come back to haunt growers

Ed DeSousa, who owns the small wholesale grow facility River Run Gardens in Newburyport, said growers who have always been meticulous about their product have less to worry about. The companies facing the greatest threat now, he said, are the ones that tried to save money by importing “clones” of trendy, out-of-state variants or fell behind on testing and sanitization.

“Those who decided to take those shortcuts to try to make some money, it's almost like cannabis karma,” DeSousa said. “If you go into this particular line of business and you are looking to maximize your profit at the stake of putting out a solid product, well, this was bound to happen.”

The virus can be detected through a genetic PCR test, a step that is not required by the Cannabis Control Commission.

By the time growers notice the signs — stunted and brittle plants, lower THC levels and discolored leaves — it’s too late to stop the spread, Masso said. By that point, growers are essentially left with one option, said Nick Masso, the CEO of Marlborough-based Indo Laboratories, an independent marijuana testing facility.

“Destroy it. Destroy everything,” he said. “And if you had that anywhere within your facility, you need to do an extremely deep clean. You can’t sell a low-quality product that has no THC, and no one will buy it.”

On a federal level, cannabis remains illegal, and shipping plants across state lines is prohibited by state law. A gray area in the regulations allows growers to acquire seeds and trimmings or “immature plants” (non-flowering and under eight inches tall) from out-of-state and disclose the plants once they reach the propagation stage.

“Typically no one really starts with seeds anymore. People usually will get clones from someone to have a little bit more of an advanced starting point,” Masso said. “There are companies out there that get seeds, but they're not always doing genetic testing.”

A call for stricter cannabis regulation

Since recreational marijuana was legalized in Massachusetts seven years ago, the industry has accelerated at a breakneck pace, Masso said, with regulators “lacking the bandwidth” to apply additional — and necessary — scrutiny.

“A lot of it depends on how much effort these companies are willing to put in to actually make sure that they’re being safe in what they’re putting out into the market,” Masso said.

In Massachusetts, the state's regulatory agency, the Cannabis Control Commission is just catching up when it comes to the importance of testing. Commissioner Bruce Stebbins says they’re building out testing and lab staff to ensure that procedures are actually compliant with regulations.

“This is still a brand new industry,” Stebbins said. “There needs to be a lot more research done on the safety of the industry.”

A 2018 Harvard study demonstrated inaccurate and wildly varied results from state-certified marijuana testing facilities in Washington state. An investigation conducted last year by journalists from Commonwealth Magazine showed inconsistencies in levels of THC and contaminants present in cannabis sold in Massachusetts.

The spread of hop latent viroid is a call to action for companies — and regulators — who have let protocols fall through the cracks in recent years, Masso said. Now, companies that didn’t want to play by the rules face serious consequences.

“There’s something very poetic about it,” he said. “I don’t take pleasure in other people's misfortune, but sometimes there's companies out there that deserve it. I just hope that someone doesn't have to get hurt for them to learn their damn lesson.”

Masso says regulation is vital in a market where many companies may just not know better, making mistakes without realizing the potential consequences. He works with 35 clients around the state, and says his lab has detected hop latent viroid at three locally-based marijuana grow facilities in the past three years.

“I’m suspicious that there are many, many more companies that have experienced this, because you’ll see the THC levels drop from the twenties to the teens,” Masso said. “It doesn’t feel like enough people in the industry understand the gravity of what this could mean.”

Massachusetts law requires marijuana testing labs to be accredited through a process that requires audits, background checks and quality assurance tests, but labs aren’t required to receive accreditation for every single test they conduct, Masso says.

“Every single thing that we do is accredited, but the clients don't know any different when it comes to labs,” he said. “That leaves a lot of room for bad actors to come into the space who don't give a damn about the science, they just want to make money.”

The state’s cannabis production industry is now the highest valued agricultural crop at $362 million annual wholesale value, according to a trade publication.

Masso says his hope is that the financial threat from hop latent viroid will force the industry to focus on consumers who use marijuana for medical purposes and could suffer if products fall off the market.

“The cannabis industry built itself on being medicinal, that’s where it got its roots,” he said. “Now it's become just a commodity and people have forgotten that it was all about treating patients, not just about getting people high and making money.”

This article was updated to include a comment from the Cannabis Control Commission.