Tag Archives: spores

June 7, 2023

Building An Integrated Pest Management Plan – Part 3

By Phil Gibson

This is the third in a series of articles designed to introduce an integrated pest management framework for cannabis cultivation facilities. To see Part One, click here. For Part Two, click here. Part Four comes out next week and covers direct control options for pest reduction. More to come!

This is Part 3: Preventive Measures

Preventive measures are a great investment in the profitability of your operations. Our objective is to ensure successful repeat harvests forever. Build your procedures with this in mind. This means maintenance and regular review. We all realize that this work can be monotonous drudgery (we know!), but these procedures will ensure your success.

Figure 1: New Air Shower Access Installation

As a summary to begin, pest access must be limited wherever possible. Employees are the first place to start, but we must also return to our site map and review our facility design and workflows. Every operation has to move plants from nursery through harvest and post-harvest. Where should cleaning happen? Of course, you have to clean up post-harvest but when should this occur during the grow cycle? What is the best way to monitor and clean environmental management systems (i.e. air, water) and what are the weaknesses in the physical barriers between operations? Let’s walk through these issues one-by-one.

Employee Access and Sterile Equipment

Follow procedures to screen and protect your employees both to eliminate pests and to avoid exposing your employees to harmful chemicals or storage areas. Look for ways to isolate your workflow from pest access. Be certain that your facility is airtight and sealed with filtration of molds, spores and live organisms in your air intake areas. Air showers at your access points are important to screen your employees on their way into your gowning areas and grow facility. Clothing should be standardized and shoe coverings or crocs should be provided for all employees that access your interior. Look for ways to stop all pests (embedded, crawling, hopping or flying) in all of your room assignments (mothers, clone, veg, flower, trim and drying). This can be improved with shoe baths, sticky mats, frequent hygiene (hand washing and cleaning stations) and procedures for entry.

Always consider requiring hair & beard nets, shoe covers and disposable gloves in plant sensitive areas.

Chemical Access & Protective Equipment

Figure 2: Example Facility Map – Understand Workflow & Barriers to Pest Access

Personal protection equipment (PPE) is very important to protect any employee that will come in contact with materials, liquids or vapors for chemical resources. Establish procedures for chemical use and train employees in the safe handling of these materials. Typical equipment includes high density chemical protective gloves, boots, respirators, Tyvek (or equivalent protective wear) suits and eye protection or goggles.

Chemical access areas and their use should be restricted to employees familiar with their authorized application. Always remember that cannabis is an accumulator plant, and it will absorb and hold onto chemical treatments. Appropriate isolation and safety procedures must be followed for chemical use. Not following these restrictions can expose your employees to dangerous chemicals or get your entire harvests rejected at testing.

Facility Map & Workflow

Because insects would like to be everywhere and they come in many types (root zone, crawling, flying, microscopic, bacterial or biofilm), the facility workflow must understand where they are and how they might migrate if they penetrate your defenses. Note airflows in your rooms and fan locations so migrations can be predicted once an infestation is located. Where are your opportunities for full clean-up and disaster recovery in your building? Where should you stage maintenance filters, test kits, water and cleaning materials. How best to clean up and dispose of sealed garbage containers or cleaning materials?

Operational Cleaning & Post-Harvest Reset

When compiling your preventative measure documents, it is critical to create a repeatable operating procedure for cleaning and sanitizing your rooms, systems, and growing spaces after each harvest. Plant material handling, cleaning surfaces and wipe methods should all be documented in your Standard Operating Procedures (SOPs). Define what “clean” is. Removing plants and plant debris is pretty clear but define how to drain reservoirs, clean pipes, change filters and clean and sterilize your rooms. Operators must be trained in these SOPs and reminded of their content on a regular schedule. This is how you avoid outbreaks that can crush your profits.

Physical Barriers & Maintenance

Document your sealed spaces and define your normal room and access door barrier interfaces. Review the status of any known cracks or gaps in your perimeter. Are there any known leaks or piping that has been seen as a risk or a problem in the past? Are there any discoloring or resident mold locations (Never happens, right?). Baseline how much time and people resource a harvest operation and cleaning effort should take. Will you do this after every harvest or compromise your risk by delaying to every third or fourth harvest? Create your barrier SOP.

Environmental Control & HVAC

Managing the air quality provided to your plants is critical to your yields. Controlling CO2, air movement rates (the leaf happy dance), humidity, air filtration and sterilization methods must be maintained and cleaned on a regular basis. Do you need to change the HEPA or other particulate filters? Is there any UV light sterilization maintenance? We have all seen the home HVAC air conduit cleaning commercials. Your commercial facility is no different. How will you clean your air and water plumbing systems? How often will you perform this full reset? When will you calibrate and data log your sensors for temperature, humidity, CO2 and water resources? Put everything about your environmental set points into your maintenance document and decide when to validate these. Molds, mildews and biofilm hazards are all waiting for unmonitored systems to open the door for access.

In Conclusion, This Week

If you’re an IPM nerd and this dynamic topic did not put you to sleep, you can read more detail and examples for your integrated pest management procedures in ourcomplete white paper for Integrated Pest Management Recommendations, download the document here.

In our next chapter, Direct Control Options, we will review what you can use to protect or recover control of your facility including both chemical and non-chemical tools and methods. In our final two chapters, we will discuss extermination of the determined pests that breach your defenses. And with great expectations, our final chapter will discuss emergency response and time to go to war!

Part Four comes out next week. See you again soon!

October 17, 2019

The Best Way to Remediate Moldy Cannabis is No Remediation at All

By Ingo Mueller

3 Comments

Consumers are largely unaware that most commercial cannabis grown today undergoes some form of decontamination to treat the industry’s growing problem of mold, yeast and other microbial pathogens. As more cannabis brands fail regulatory testing for contaminants, businesses are increasingly turning to radiation, ozone gas, hydrogen peroxide or other damaging remediation methods to ensure compliance and avoid product recalls. It has made cannabis cultivation and extraction more challenging and more expensive than ever, not to mention inflaming the industry’s ongoing supply problem.

The problem is only going to get worse as states like Nevada and California are beginning to implement more regulations including even tougher microbial contamination limits. The technological and economic burdens are becoming too much for some cultivators, driving some of them out of business. It’s also putting an even greater strain on them to meet product demand.

It’s critical that the industry establishes new product standards to reassure consumers that the cannabis products they buy are safe. But it is even more critical that the industry look beyond traditional agricultural remediation methods to solve the microbial problems.

Compounding Risks

Mold and other microbial pathogens are found everywhere in the environment, including the air, food and water that people consume. While there is no consensus yet on the health consequences of consuming these contaminants through cannabis, risks are certainly emerging. According to a 2015 study by the Cannabis Safety Instituteⁱ, molds are generally harmless in the environment, but some may present a health threat when inhaled, particularly to immunocompromised individuals. Mycotoxins resulting from molds such as Aspergillus can cause illnesses such as allergic bronchopulmonary aspergillosis. Even when killed with treatment, the dead pathogens could trigger allergies or asthma.

Photo credit: Steep Hill- a petri dish of mold growth from tested cannabis

There is an abundance of pathogens that can affect cannabis cultivation, but the most common types are Botrytis (bud rot, sometimes called gray mold) and Powdery Mildew. They are also among the most devastating blights to cannabis crops. Numerous chemical controls are available to help prevent or stem an outbreak, ranging from fungicides and horticultural oils to bicarbonates and biological controls. While these controls may save an otherwise doomed crop, they introduce their own potential health risks through the overexposure and consumption of chemical residues.

The issue is further compounded by the fact that the states in which cannabis is legal can’t agree on which microbial pathogens to test for, nor how to test. Colorado, for instance, requires only three pathogen tests (for salmonella, E. coli, and mycotoxins from mold), while Massachusetts has exceedingly strict testing regulations for clean products. Massachusetts-based testing lab, ProVerde Laboratories, reports that approximately 30% of the cannabis flowers it tests have some kind of mold or yeast contamination.

If a cannabis product fails required microbial testing and can’t be remedied in a compliant way, the grower will inevitably experience a severe – and potentially crippling – financial hit to a lost crop. Willow Industries, a microbial remediation company, says that cannabis microbial contamination is projected to be a $3 billion problem by 2020ⁱⁱ.

Remediation Falls Short
With the financial stakes so high, the cannabis industry has taken cues from the food industry and adopted a variety of ways to remediate cannabis harvests contaminated with pathogens. Ketch DeGabrielle of Qloris Consulting spent two years studying cannabis microbial remediation methods and summarized their pros and consⁱⁱⁱ.

He found that some common sterilization approaches like autoclaves, steam and dry heat are impractical for cannabis due the decarboxylation and harsh damage they inflict on the product. Some growers spray or immerse cannabis flowers in hydrogen peroxide, but the resulting moisture can actually cause more spores to germinate, while the chemical reduces the terpene content in the flowers.

Powdery mildew starts with white/grey spots seen on the upper leaves surface

The more favored, technologically advanced remediation approaches include ozone or similar gas treatment, which is relatively inexpensive and treats the entire plant. However, it’s difficult to gas products on a large scale, and gas results in terpene loss. Microwaves can kill pathogens effectively through cellular rupture, but can burn the product. Ionizing radiation kills microbial life by destroying their DNA, but the process can create carcinogenic chemical compounds and harmful free radicals. Radio frequency (which DeGabrielle considers the best method) effectively kills yeast and mold by oscillating the water in them, but it can result in moisture and terpene loss.

The bottom line: no remediation method is perfect. Prevention of microbial contamination is a better approach. But all three conventional approaches to cannabis cultivation – outdoors, greenhouses and indoor grow operations – make it extremely difficult to control contamination. Mold spores can easily gain a foothold both indoors and out through air, water, food and human contact, quickly spreading into an epidemic.

The industry needs to establish new quality standards for product purity and employ new growing practices to meet them. Advanced technologies can help create near perfect growing ecosystems and microclimates for growing cannabis free of mold contamination. Internet of Things sensors combined with AI-driven robotics and automation can dramatically reduce human intervention in the growing process, along with human-induced contamination. Natural sunlight supplemented with new lighting technologies that provide near full-light and UV spectrum can stimulate robust growth more resistant to disease. Computational fluid dynamic models can help growers achieve optimal temperature, humidity, velocity, filtration and sanitation of air flow. And tissue culture micropropagation of plant stock can eliminate virus and pathogen threats, to name just a few of the latest innovations.

Growing legal cannabis today is a risky business that can cost growers millions of dollars if pathogens contaminate a crop. Remediation methods to remove microbial contamination may work to varying degrees, but they introduce another set of problems that can impact consumer health and comprise product quality.

References

i. Holmes M, Vyas JM, Steinbach W, McPartland J. 2015. Microbiological Safety Testing of Cannabis. Cannabis Safety Institute. http://cannabissafetyinstitute.org/wp-content/uploads/2015/06/Microbiological-Safety-Testing-of-Cannabis.pdf

ii. Jill Ellsworth, June 2019, Eliminating Microbials in Marijuana, Willow Industries, https://willowindustries.com/eliminating-microbials-in-marijuana/#

iii. Ketch DeGabrielle, April 2018, Largest U.S. Cannabis Farm Shares Two Years of Mold Remediation Research, Analytical Cannabis, https://www.analyticalcannabis.com/articles/largest-us-cannabis-farm-shares-two-years-of-mold-remediation-research-299842

March 23, 2016

A Case for Compartmentalization: Problems with Perpetual Harvest Models in Cultivation, Part I

By Adam Koh

7 Comments

When newspapers and television run a cannabis story, it is frequently accompanied by photos or video of vast, cavernous warehouses filled with veritable oceans of plants. Photos used to illustrate stories in the New York Times and Denver Post serve to illustrate this point.

This type of facility design is sometimes referred to in the cannabis industry as a “perpetual harvest” model. This is because plants are harvested piecemeal – one row at a time, for example – with new plants ready to flower replacing the recently harvested ones. In this model, flowering plants of various ages occupy the same space and the room is never completely harvested and empty, hence the “perpetual” moniker. This is in contrast to more compartmentalized facility designs, in which flowering plants are segregated in smaller groups in various rooms, which are then harvested completely before the room is cleaned and new plants ready to flower replace the previous ones.

The perpetual harvest setup appears impressive and lends itself well to portraying the volume of production being achieved in large facilities. This is likely why I have seen such models, or similar ones, copied in other states. Prospective entrants to the industry have also approached my firm with such designs in mind for their cultivation facilities. However, we generally advise against the perpetual harvest facility model, as this type of design imposes serious difficulties upon operators. Problems arise primarily in the areas of pest and contamination mitigation, ability to properly observe pesticide use and worker safety guidelines, and inefficiencies in lighting and HVAC usage. The problems noted are linked to the perpetual harvest design and can be mitigated with increased compartmentalization. Before getting to my recommendations, however, lets run down the issues created by the perpetual harvest model.

AdamKohcultivation — Photo credit: Denver Post

Lighting and HVAC Inefficiencies

In many photos I see of perpetual harvest facilities, the ceilings are extremely high, as are the light fixtures in most cases. This is likely the result of one of the main perceived advantages of such spaces, which is that they require minimal construction prior to getting up and running. There are no walls to be put up or ceilings lowered, and the lack of compartmentalization makes running wires and ducting much easier.

However, whatever capital was saved in initial construction will likely be burned up by increased ongoing operational costs. High ceilings such as those in the above photos mean more cubic footage that climate control systems must cool or heat. Additionally, due to the great height of the light fixtures, plants are not getting the most bang for their buck, so to speak, compared to designs that allow lights to be lowered appropriately to provide optimal intensity and spectrum. Double-Ended High Pressure Sodium (DE HPS) lamps are probably the most common type of lighting in use for flowering by commercial cannabis cultivators today, and they are ideally situated about four feet above the canopy when running at full capacity.

For businesses aiming for a no-frills production model with minimal attention to the light management needs of individual cannabis cultivars (or strains, as they are commonly referred to), then this consideration may be moot. However, those operations attempting to produce the highest-quality flower and plant material know the value of proper light management, as well as the fact that some cultivars respond differently than others to intense light. Indeed, I have observed cultivars that produce more when light intensity was decreased, while others thrived under intense light that would have seriously damaged others. This makes the one-size-fits-all approach to light management I’ve seen in most perpetual harvest designs generally detrimental to the quality of the final product, in addition to using the same amount of energy, or more, to achieve that lower quality result.

Difficulties in Pest and Contamination Mitigation

Such a design makes it easy for a small pest incursion to become a full-blown infestation. Because plants about to be harvested are sharing space with plants just beginning their flowering process, this means that both current and future harvests will be affected, or even lost entirely if the pest problem is severe. Having plant groups of different ages share the same space is generally unadvisable. This is because older plants, particularly those close to harvest, are weaker and more susceptible to pests by virtue of the fact that their life cycles are nearing an end. On the other hand, a more compartmentalized facility design provides physical barriers that can contain mites and mildew spores to some extent, limiting the damage done by individual pest incursions.

One of the essential tasks in an indoor cultivation operation is sterilizing just-harvested spaces to ensure that the subsequent run gets off to a clean start. This task could conceivably be performed in a perpetual harvest model; say, for example, trays, trellis frames, and other equipment are scrubbed after a row has been cut down and removed for drying or processing. However, due to the fact that there are always other plants in the room, it seems impossible for any plant group to get an assuredly clean start, as other plants may be harboring bugs, mold spores, or viruses, despite not showing signs or symptoms. The presence of plants also eliminates the possibility of using cleaning agents such as bleach, which gives off harmful fumes, but is sometimes necessary to completely sterilize an area that might have previously experienced some amount of powdery mildew or botrytis.

In Part II of this series, I will discuss some problems with pesticide use and worker safety regulations as well as provide recommendations for compartmentalization in cultivation facilities. Stay tuned for Part II of A Case for Compartmentalization: Problems with “Perpetual Harvest” Models in Cultivation, coming out next week.