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90% of cannabis farms are infected with a dangerous and deadly pathogen

An infectious pathogen is currently spreading widely in California’s cannabis farms. This scourge is attacking plants and growing invisibly for months before spoiling crops.

This happens just as farmers are getting ready to harvest. Scientists believe it currently affects over 90 percent of farms. it will cause billions of dollars in damages to the national cannabis economy.

What is this pathogen attacking cannabis farms?

The hop-latent viroid (HLVd) was first identified in hop plants (close relatives of cannabis) in the 1980s. It shrivels cannabis plants, reducing how much weight they produce by as much as 30 percent.

The pathogen also destroys the plants’ amount of THC (marijuana’s main psychoactive compound). This decreases their value dramatically.

Although this pathogen has likely been spreading in cannabis farms for over a decade, growers were clueless. At first they didn’t know what was harming their harvests.

Damage only occurred at the end of the crop’s life cycle. This makes the pathogen eve more dangerous.

Farmers usually grow cannabis by cutting small pieces off of one plant. They refer to this as the “mother,” and use it to propagate hundreds of new plants.

To keep producing offspring, growers artificially prevent these mother plants from growing flowers. This means they can silently spread the pathogen for months without showing any signs of disease. 

Researchers didn’t identify this cannabis farm pathogen until 2019

HLVd was first identified in California in 2019 in samples from a Santa Barbara cannabis farm. BY 2021, it had spread to at least 90 percent of the state’s farms.

Scientists believe it has spread in other states, as well as in Europe. The HLVd pathogen has become the “biggest concern for cannabis” growers worldwide. This, according to a recent scientific paper.

New rapid test available

Fortunately, Purple City Genetics figured out how to help. The Oakland-based startup, Purple City, focuses on breeding and cultivating cannabis phenotypes.

This year, they released a new HLVd test that can be conducted on site. It delivers results in just a few hours. This is much faster than previous methods for identifying HLVd infections.

Those involved farmers mailing samples to labs. They would then wait for days or even weeks to get the results.

“By the time you get the results back you may have cut that plant and sold it to your customers. So there is a real need for a high throughput onsite diagnostic test for hop-latent viroid,” said Ali Bektaş, the CEO of Purple City. 

New tech called LAMP is helping save cannabis farms

To overcome this problem, Bektaş adapted a technique called LAMP. He worked this tech on during his doctoral studies in Microbial Ecology at the University of California, Berkeley.

This method became very popular during the Covid-19 pandemic. Unlike PCR tests that require specialized lab equipment and expert technicians, it uses cheap equipment.

LAMP can be accurately operated by nearly anyone. It delivers results in just a few hours. Recently, the company has started to sell this technology worldwide for $10 a test.

“We didn’t just identify a great test that is accurate, but it’s [also] easy to use and it doesn’t require a high level of expertise. You can take microbiology to the public and put it in their hands…It’s important for people to have this type of testing,” concluded Luke Horst, the director of business development for Purple City Genetics.

A recent scientific article discussing the features and spread of HLVd was published in the journal Viruses.

Additional threats to cannabis farms

Cannabis farms, like any agricultural operation, face a number of potential threats that can affect their viability and profitability. Here are several key threats:

Pests, pathogens and diseases

Cannabis plants can be vulnerable to a wide variety of pests, including aphids, spider mites, and various kinds of mold and mildew. Controlling these pests can be challenging and may require significant investment in pest control measures.

Weather conditions

Cannabis farms can be adversely affected by harsh weather conditions. Cold temperatures, high winds, excessive rain, or prolonged drought can all potentially damage crops and lower yields. Moreover, cannabis is a crop that prefers consistent sunlight, and cloudy or shaded conditions can impact growth.

Regulatory changes

In many regions, the legality of cannabis cultivation is still relatively new and subject to change. Regulatory changes could potentially limit the amount of cannabis that can be grown, change licensing requirements, or even criminalize certain kinds of cultivation.

Market fluctuations

The cannabis industry has experienced significant growth in recent years, but it remains a relatively new and volatile market. Prices can fluctuate wildly, and changes in supply and demand can impact profitability.


Theft is a significant concern for many cannabis farms, as the crop can be very valuable and highly sought after. This can necessitate significant investment in security measures, such as fencing, cameras, and security personnel.

Environmental impact and sustainability

There’s an increasing societal pressure for sustainable and environmentally friendly agricultural practices. Water consumption, energy use for indoor farms, pesticide use, and waste management are all environmental issues that cannabis farms must address.

Cannabis is a highly regulated industry. There are laws about who can grow cannabis, where it can be grown, how it can be grown, how it can be sold and advertised, etc. Failure to comply with these laws can lead to heavy fines, license revocation, or even criminal charges.

Lack of banking and financial services

Despite cannabis being legal in many places, banking services are often unavailable to cannabis businesses. This is due to federal regulations in the United States. No banking access can make it hard for cannabis businesses to secure loans, handle cash, or manage other financial needs.

Understanding and managing these threats is crucial to the success of any cannabis farming operation. Many of these challenges are common to other types of agriculture.

However, some are unique to the cannabis industry. Due to how relatively new the industry is, issues need to be overcome. This is especially due to the unique legal and regulatory environment in which it operates.


By Andrei Ionescu, Staff Writer

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