According to the Oregon Department of Agriculture, the cannabis aphid can cause wilting and yellowing, but it is not as destructive as the dreaded hemp russet mite.
In the past, a visit from a government official was the last thing a cannabis grower would ever want. Even after the legalization of medical marijuana, most cultivators preferred to keep state regulators at an arm’s length — if not further — away from their garden.
But legalization has brought about a completely new phenomenon: growers who willingly interact with state officials.
In lieu of the agricultural extension programs available for other crops, the Oregon Department of Agriculture has been providing some limited services to cannabis growers.
Although the agency doesn’t have the funding to do too much research at the moment, entomologist Joshua Vlach has been looking at pest concerns for about two years now. During one of these pest inspections, Vlach discovered a couple grows that had infestations of the cannabis aphid, a species not previously seen in Oregon.
The cannabis aphid (Phorodon cannabis) is not a new species by any means. But the recent discovery in Oregon was the first time the pest had been officially identified in the state.
“How it got into the state, I suppose, is a mystery, since we don’t technically have interstate movement of plants,” Vlach says. “Maybe it’s been here a long time and it was just in the background.”
The aphid showed up for the first time in November 2017, then again at another grow in December, both in the Portland metropolitan area. The cannabis aphid does not look significantly different than other aphids. The only way to tell them apart is the small, distinctive hairs on the body. Most people would just assume they’re dealing with something like a green peach aphid, not realizing they have a specialist that has adapted to cannabis specifically.
“The reason someone brought it to me was that they were using a bio-control program for aphids that had been working,” Vlach says. “And then all of a sudden, the program stopped working.”
So far, Vlach says the cannabis aphid has been very specific to marijuana plants. There’s a possibility that it could jump to hops, but that’s really the only other crop that might be in any danger.
The cannabis aphid can cause wilting and yellowing — annoying, but certainly not as destructive as the hemp russet mite.
“It seems to be such an early introduction that the community should be able to stop its spread,” Vlach says.
However, the appearance of cannabis aphids in Oregon highlights the vast difference in pest management between marijuana growers and traditional farmers. In most agriculture sectors, growers pool their resources through trade groups to grant funding for research. For instance, grass growers might want to focus on controlling slugs or wine grape growers might want more information about thrips. By working collectively, growers associations have funded decades’ worth of research into their focus crops.
Cannabis growers, on the other hand, simply haven’t followed this established game plan — therefore, the marijuana industry is missing some fundamental, experimental research.
“In that sense, they’re not moving forward in terms of collective knowledge,” Vlach says. “The cannabis industry is trying to reinvent the wheel. Cannabis is not that different of a crop.”
When a pest outbreak happens, cannabis growers end up fighting the same pest independently. Rather than working together as colleagues, they approach the situation as rivals and competitors.
“With this mean, dog-eat-dog version, then everyone’s going to get burned at some point,” Vlach says. “They’ll get it under control in the long term, but it will cost everybody some money. If we have this communal bunch of information, everybody will be financially protected. “
Even with well-established crops, new pests are discovered all the time, Vlach says, with about 1 in 7 turning out to be an economic pest.
“The thing is, no matter how experienced you are, there are pests and diseases that people have never dealt with before that will be new to everyone at some point,” Vlach says. However, he cautions people against putting too much stock in unsubstantiated information found on the Internet.
“Some of the stuff online is very much word of mouth — not quite an old wives’ tale — but there’s a lot of information that isn’t validated by good research,” he says. “Some of the things I see out there don’t seem like they could do anything.”
Cannabis is not the only plant with restrictions on interstate transport — but people will often skirt those rules, despite the potential for disaster. One example is the case of the filbert mite, which, Vlach says, “was brought in from the East by somebody who was thumbing his nose at the law.”
Vlach says the invasive mite nearly wiped out the hazelnut industry in the West. Now, breeders have been able to develop filbert plants that are resistant to the pest, so the industry has been able to make a comeback. It’s an example he hopes the cannabis industry learns from before it’s too late.
“I always encourage folks that if they see something they’ve never seen before, they should bring it to our attention,” Vlach says.