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June 27, 2023

Building An Integrated Pest Management Plan – Part 5

By Phil Gibson

This is the fifth in a series of articles designed to introduce an integrated pest management framework for cannabis cultivation facilities. To see Part One, an overview of the plan and pest identification, click here. For Part Two, on pest monitoring and record keeping, click here. For Part Three, on preventative measures, click here. For Part Four, control methods, click here. Our final chapter, Part Six, discussing emergency response, comes out next week to wrap it all up.

This is Part 5: Pest Control – Taking Action

Previous chapters have covered the many preparations you can take to protect your facilities from pest attacks and outbreaks before they get started. This chapter will summarize the concepts of pest control thresholds and the actions you can take for the painful event when you surpass those limits (and various examples). The Integrated Pest Management (IPM) recommendations provide you with a framework for these plans.

Figure 1: Cleaning regimen, the heart of successful operations – no biofilm buildups

Preventative actions are part of your regular site operations; in other words, they are how you avoid problems before they happen. Just to hit this action one more time: cleaning must be fundamental to your facility. Water sanitation and changing filters must be done on schedule and frequently to avoid biofilm build up and nasty self-multiplying eco-systems.

For each of the rooms in your facility, identify the acceptable tolerance level for each type of pest that you may encounter. Define the intervention levels per room: preventative, direct action and escalated direct action. Follow your predefined procedures and defend your facility. Let’s cover high, medium and low tolerance example responses.

High Threshold for Tolerance

For example, the impact on your plants, your profits and your yields from the discovery of a white fly fluttering inside of one of your flower rooms may be very small. If this presence is late in your harvest cycle, your tolerance of this discovery may be very high. Your team could take preventative actions to clean the room more aggressively or to check your traps more frequently, but you are probably not going to want to invest in aggressive actions at that time in the harvest cycle.

Move from passive observation to the shake test. With sticky traps in place, shake or brush your plants. Do you see the bug counts increase on your test sheets?

Figure 2: Thrip Evidence c/o UC ANR Publication 7429

As that infestation grows, you may set a threshold for direct action (i.e. 5-10 flies per trap per week). If you reach that level, implement a treatment action with a non-chemical microbial biofungicide to stop growth in the roots or neem oil as a direct chemical action.

When you reach your escalated threshold of 10-20 flies per trap or direct plant damage is apparent, an infestation is more serious. In that event, you may choose to take steps to directly reduce the pest population with knock down sprays of approved direct chemical pesticides like citric acid or insecticidal soaps. Be sure to use your Personal Protective Equipment (PPE) for breathing and contact safety if you get into this situation.

Medium Threshold for Tolerance

Depending on the timing in your harvest cycle, the discovery of fungus gnats in your grow room may trigger a medium level alarm for you. Is the location, a small example with a minimal frequency? Is this addressable with additional attention to cleaning the area and longer dry periods in the irrigation or is this the beginnings of an infestation? Fungus gnats feed off of fungus or organic matter in soil triggered from an overly moist root environment. You may choose to react with immediate cleaning at the first existence in a room. Or you could set your “Medium” level alert status to be additional sticky trap distribution at the first visible gnat. If those counts reach 10-20 gnats per sticky trap per week, begin your foliar spray regimen with Zerotol or the equivalent.

If these counts do not respond to your treatment, meaning that the next sticky trap count reaches beyond 20+ gnats per trap or visible direct plant damage, then institute your root drench protocol with a solution of BActive 1-2 times per week until the problem is under control and the counts are reduced. If the growth continues, look to approved pesticides in your area (as an example, AzaGuard Asadirectin).

Low Threshold for Tolerance

Alternatively, you may have a unified air circulation system due to facility limitations. Your air circulation may be shared across all of your mother plants, clones, veg and flowering plant areas. In that case, any presence of an airborne fungal infection like powdery mildew would have a very low tolerance of acceptance. Selective de-leafing of the infection and increased airflow are your first defense. Any visible presence beyond that would trigger a low threshold alert and immediately start a preventative action, such as carefully removing the infected plant material much wider than a few leaves and treating the area with foliar sprays like Zerotol (hydrogen peroxide plus).

If the penetration continues or expands, treatment would escalate to minimal risk pesticide follow up and observation. Chemical oils or citric acid might be in your mix in this case.

Finally, if repetitive treatments once a week are not turning the tide, increasing to once per day or even once per ON/OFF lighting cycle until the infection is controlled. At this point, you may decide to strip the room down and start over. Clearly the choice to “throw in the towel” is a total loss of the crop, but it may be the best option relative to minimal yields and failed flowers that will not sell.

Pest Control Actions

Our Integrated Pest Management recommendations paper gives you examples of what to consider for plans with white flies, fungus gnats, root aphids, powdery mildew and biofilm on plumbing or surfaces. These follow the preventative action, direct action, escalated direct action and pesticide approaches for each example. These are options to plan for water sources, root treatment, tunneling, crawling and flying phases.

In summary this week

As covered, preventative measures are your best defense. Hire expert consultants and plan these well. Escalate your response based on your scouting activity and your plan. Add your sticky traps, de-leafing, root drench, foliar sprays or knock down sprays as defined by your pest population control actions document.

For more detail on each of these treatments, you can see examples for your integrated pest management procedures in our complete white paper for Integrated Pest Management Recommendations, download the document here.

In our final chapter, Emergency Response, we will review control thresholds and example plans for a range of problems from biofilm build up to white flies and more.

Our final chapter after will describe emergency response framework and reviewing your complete plans. See you next week.

December 7, 2022

The 3-Legged Stool of Successful Grow Operations: Climate, Cultivation & Genetics – Part 4

By Phil Gibson

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This is Part 4 in The 3-Legged Stool of Successful Grow Operations series. Click here to see Part 1, here to see Part 2, and here to see Part 3. Stay tuned for Part 5, coming next week.

Integrated Pest Management (IPM)

Aeroponic & hydroponic systems can operate with little to no soil or media. This eliminates the pest vectors that coco-coir, peat moss/perlite and organic media can harbor as part of their healthy biome approach. Liquid nutrient systems come at the nutrient approach from a different direction. Pure nutrient salts (nitrogen, potassium, magnesium and trace metals) are provided to the plant roots in a liquid carrier form. This sounds ideal for integrated pest management programs, but cultivators have to be aware of water and airborne pathogens that can disrupt operations. I will summarize some aspects to consider in today’s summary.

The elimination of soil media intrinsically helps a pest management program as it reduces the labor required to maintain a grow and the number of times the grow room doors are opened. Join that with effective automation with sensors and software, and you have immediate improvements in pest access. Sounds perfect, but we still have staff to maintain a facility and people become the number one source of contamination in a grow operation.

Figure 1: Example of Pythium Infected & Healthy Roots

Insects do damage directly to plants as they grow and procreate in a grow room. They also carry other pathogens that infect your plants. For example, root aphids, a very common problem, are a known carrier of the root pathogen, Pythium.

Procedures

One of the most common ways for pests to access your sealed, sterile, perfectly managed facilities are in the root stock of outsourced clones. If you must start your grow cycles with externally sourced clones, it is strongly recommended that you quarantine those clones to make sure that they do not import pest production facilities into your operation. Your operation management procedures must be complete. If you take cuttings from an internal nursery of mother plants, any pathogens present in your mother room will migrate through cuttings into your clones, supply lines, and subsequently, flower rooms.

Figure 2: Healthy Mothers & Clones, Onyx Agronomics

Start your gating process with questioning your employees and visitors. Do they grow at home or have they been to another grow operation in the last week? In the last day? You may be surprised by how many people that gain access to your grow will answer these questions in the affirmative.

Developing standard operating procedures (SOPs) that are followed by every employee and every visitor will significantly reduce your pest access and infection rates, and hence, increase your healthy harvests and increase your profitability. Procedures should include clothing, quarantining new genetics and cleaning procedures, such as baking or irradiating rooms to guarantee you begin with a sterile facility. This is covered more in the complete white paper.

Engineering Controls

Technology is a wonderful thing but no replacement for regimented procedures. Considered a best practice, professional air showers, that bar access to internal facilities, provide an aggressive barrier for physical pests. These high velocity fan systems and exhaust methods blow off insects, pollen and debris before they proceed into your facility. From that access port into your grow space, positive air flow pressure should increase from the grow rooms, to the hallways, to the outside of your grow spaces. This positive airflow will always be pushing insects and airborne material out of your grow space and away from your plants.

Maintaining Oxidation Reduction Potential (ORP)

ORP is a relative measurement of water health. Perfect water is clear of all material, both inert and with life. Reverse osmosis (RO) is a standard way to clear water but it is not sufficient in removing microscopic biological organisms. UV and chemical methods are needed in addition to RO to clear water completely.

ORP is an electronic measurement in millivolts (mV) that represents the ability of a chemical substance to oxidize another substance. ORP meters are a developing area and when using a meter, it is important to track the change in ORP values rather than the absolute number. This is due to various methods that the different meters use to calculate the ORP values. More on this in the white paper.

Oxidizers

Figure 4: AEssenseGrows Aeroponic Nozzles

There are two significant ways to adjust the ORP of a fertilizer/irrigation (fertigation) solution. The first is by adding oxidizers. Examples are chemical oxidizers like hydrogen peroxide (H2O2), hypochlorous acid (HOCl), ozone (O3) and chlorine dioxide (ClO2). Adding these to a fertigation solution increases the ORP of the fertigation solution by oxidizing materials and organic matter. The key is to kill off the bad things and not affect the growth of plants. Again here, the absolute ORP metric is not the deciding factor in the health of a solution and the methods by which each chemical reaction occurs for each of these chemicals are different. This is compounded by the fact that different ORP meters will show different readings for the same solution.

Another wonderful thing about automation and aeroponic and hydroponic dosing systems is that they can automatically maintain oxidizing rates and our white papers explain the methods executed by today’s automation systems.

Water Chilling

Another way to adjust ORP is to reduce the water temperature of the reservoirs. Maintaining water temperature below the overall temperature of your grow rooms is imperative for minimal biological deposition and nutrient system health. Water chillers use a heat exchanger process to export heat from liquid nutrient dosing reservoirs and maintain desired temperatures.

The benefit of managing ORP in aeroponic and hydroponic grow systems is highly accelerated growth. This is enhanced in aeroponics due to the effectively infinite oxygen exchanging gases at the surface of the plant roots. Nutrient droplets are sprayed or vaporized in parallel and provided to these root surfaces. Maximizing the timing and the best mineral nutrients to the root combustion is the art of grow recipe development. Great recipes drive superior yields and when combined with superior genetics and solid environmental controls, these plants will deliver spectacular profits to a grow operation.

Another Hero Award

Before closing this chapter, we have many cultivators that are producing stellar results with their operational and IPM procedures, so it is hard to choose just one leader. That said, our hats are off to RAIR Systems again and their director of cultivation, Ashley Hubbard. She and her team are determined to be successful and drive pests out of their operations with positive “little critters” and the best water treatment and management that we have seen. You are welcome to view the 7-episode walkthrough of the RAIR facility and their procedures here.

To download the complete guide and get to the beef quickly, please request the complete white paper Top Quality Cultivation Facilities here.

Stay tuned for Part 5 coming next week where we’ll discuss Genetics.

October 17, 2019

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

By Ingo Mueller

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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

January 30, 2018

10 Treatment Methods to Reduce Mold in Cannabis

By Ketch DeGabrielle

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As the operations manager at Los Sueños Farms, the largest outdoor cannabis farm in the country, I was tasked with the challenge of finding a yeast and mold remediation treatment method that would ensure safe and healthy cannabis for all of our customers while complying with stringent regulations.

While outdoor cannabis is not inherently moldy, outdoor farms are vulnerable to changing weather conditions. Wind transports spores, which can cause mold. Each spore is a colony forming unit if plated at a lab, even if not germinated in the final product. In other words, perfectly good cannabis can easily fail microbial testing with the presence of benign spores.

Fun Fact: one square centimeter of mold can produce over 2,065,000,000 spores .

If all of those landed on cannabis it would be enough to cause over 450 pounds of cannabis to fail testing, even if those spores remained ungerminated.

It should also be known that almost every food item purchased in a store goes through some type of remediation method to be considered safe for sale. Cannabis is finally becoming a legitimized industry and we will see regulations that make cannabis production look more like food production each year.

Regulations in Colorado (as well as Nevada and Canada) require cannabis to have a total yeast and mold count (TYMC) of ≤ 10,000 colony forming units per gram. We needed a TYMC treatment method that was safe, reliable, efficient and suitable for a large-scale operation. Our main problem was the presence of fungal spores, not living, growing mold.

Below is a short list of the pros and cons of each treatment method I compiled after two years of research:

Autoclave: This is the same technology used to sterilize tattoo needles and medical equipment. Autoclave uses heat and pressure to kill living things. While extremely effective, readily available and fiscally reasonable, this method is time-consuming and cannot treat large batches. It also utilizes moisture, which increases mold risk. The final product may experience decarboxylation and a change in color, taste and smell.

Dry Heat: Placing cannabis in dry heat is a very inexpensive method that is effective at reducing mold and yeast. However, it totally ruins product unless you plan to extract it.

Gamma Ray Radiation: By applying gamma ray radiation, microbial growth is reduced in plants without affecting potency. This is a very effective, fast and scalable method that doesn’t cause terpene loss or decarboxylation. However, it uses ionizing radiation that can create new chemical compounds not present before, some of which can be cancer-causing. The Department of Homeland Security will never allow U.S. cannabis farmers to use this method, as it relies on a radioactive isotope to create the gamma rays.

Gas Treatment: (Ozone, Propylene Oxide, Ethylene Oxide, Sulfur Dioxide) Treatment with gas is inexpensive, readily available and treats the entire product. Gas treatment is time consuming and must be handled carefully, as all of these gases are toxic to humans. Ozone is challenging to scale while PPO, EO and SO2 are very scalable. Gases require special facilities to apply and it’s important to note that gases such as PPO and EO are carcinogenic. These methods introduce chemicals to cannabis and can affect the end product by reducing terpenes, aroma and flavor.

Hydrogen Peroxide: Spraying cannabis plants with a hydrogen peroxide mixture can reduce yeast and mold. However, moisture is increased, which can cause otherwise benign spores to germinate. This method only treats the surface level of the plant and is not an effective remediation treatment. It also causes extreme oxidation, burning the cannabis and removing terpenes.

Microwave: This method is readily available for small-scale use and is non-chemical based and non-ionizing. However, it causes uneven heating, burning product, which is damaging to terpenes and greatly reduces quality. This method can also result in a loss of moisture. Microwave treatment is difficult to scale and is not optimal for large cultivators.

Radio Frequency: This method is organic, non-toxic, non-ionizing and non-chemical based. It is also scalable and effective; treatment time is very fast and it treats the entire product at once. There is no decarboxylation or potency loss with radio frequency treatment. Minimal moisture loss and terpene loss may result. This method has been proven by a decade of use in the food industry and will probably become the standard in large-scale treatment facilities.

Steam Treatment: Water vapor treatment is effective in other industries, scalable, organic and readily available. This method wets cannabis, introducing further mold risk, and only treats the product surface. It also uses heat, which can cause decarboxylation, and takes a long time to implement. This is not an effective method to reduce TYMC in cannabis, even though it works very well for other agricultural products

extraction equipment — Extraction can be an effective form of remediating contaminated cannabis

Extraction: Using supercritical gas such as butane, heptane, carbon dioxide or hexane in the cannabis extraction process is the only method of remediation approved by the Colorado Marijuana Enforcement Division and is guaranteed to kill almost everything. It’s also readily available and easy to access. However, this time-consuming method will change your final product into a concentrate instead of flower and usually constitutes a high profit loss.

UV Light: This is an inexpensive and readily available method that is limited in efficacy. UV light is only effective on certain organisms and does not work well for killing mold spores. It also only kills what the light is touching, unless ozone is captured from photolysis of oxygen near the UV lamp. It is time consuming and very difficult to scale.

After exhaustively testing and researching all treatment methods, we settled on radio frequency treatment as the best option. APEX, a radio frequency treatment machine created by Ziel, allowed us to treat 100 pounds of cannabis in an hour – a critical factor when harvesting 36,000 plants during the October harvest.