8 Core Components of a Cannabis IPM Program
Integrated Pest Management (IPM) programs are holistic systems to manage pest pressures below the threshold of economic damage.
The world is a dangerous place for cannabis plants.
IPM programs will vary depending on region and method of production, but most will share these eight core components.
The 8 Core IPM Components:
1) Prevention:
2) Genetic Resistance:
3) Continuity:
4) Observation:
5) Biological controls:
6) Chemical Controls:
7) Climate Management:
8) Mechanical Controls:
1) Prevention:
The first component of IPM is prevention. Prevention includes biosecurity and quarantine practices to exclude pathogens and pests from protected cultivation areas. There are several ways that pests can enter cultivation areas.
Showers are generally provided for personnel and clean scrubs, or clothing covers (bunny suits) are required to enter production areas.
Staff usually keep a dedicated pair of shoes on site, that are only worn in production areas, and are sanitized frequently. Gloves are often mandated, but studies have shown frequent handwashing to be more effective in avoiding cross-contamination.
Footbaths containing sanitizing solution are located at entrances to minimize contamination between grow areas. Dedicated horticulture, and sanitation tools are kept in each production area, and sanitized as per Standard Operating Procedures (SOPs).
All surfaces within cultivation areas are sanitized on a schedule, and a deep cleaning is performed following each crop cycle.
Environment
Pests and Pathogens are often present in the outside environment and can enter cultivation areas where they may find a protected niche to infest.
Air exchange should be controlled and filtered to minimize this possibility.
Many indoor facilities operate within sealed environments, and pathogens can be very effectively excluded by air lock, and air filtration practices. Air filtration usually involves a two-step system where a filter of MERV-13 rating or better is used to remove particulates. The second step is a downstream uvc treatment to kill any spores that remain in the air column.
In greenhouses, which require high rates of air exchange to manage climate factors, the complete exclusion of airborne pathogens through air filtration is unrealistic.
Other possible vectors from the outside environment include flying insects, and ants which will bring aphids into a facility to farm them.
2) Genetic Resistance:
Cannabis cultivars differ greatly in their evolved resistance to various pests. Selecting cultivars with high resistance to the pest pressures that are present in the production environment is crucial.
Healthy plants are best able to fend off pathogens, and good horticultural practices are a baseline for any IPM program.
In some cases, genetic resistance can offer strong protection against pest pressures that are otherwise very difficult to manage. Notably, a cannabis resistance gene has been recently discovered that imparts total immunity to the Golovinomyces ambrosiae pathogen responsible for many Powdery Mildew infections.
This discovery has the potential to eliminate billions of dollars in crop loss to this prevalent disease. Discovery of genetic resistance is not limited to research laboratories.
Large scale cultivators would be wise to continually trial cultivars to establish fitness for production in their environments.
3) Continuity:
An important principal of successful IPM programs is continuity of care. From creation to post-harvest, all plants need to be continually managed to keep pest pressures at the lowest possible level.
Cuttings should always be taken from vigorous, healthy mother stock. The cloning process usually involves humidity, temperature, and stagnant air conditions which favor fungal pathogen establishment.
Care is taken when moving plants between locations within a production facility.
Young plants can be effectively treated with sprays or dips to ensure full coverage of all plant surfaces.
Beneficial predator populations can be established on young plants.
As plants enter later developmental stages, pest management options narrow, so early and aggressive treatments are recommended.
4) Observation:
Observation is a central component of pest management programs. All crop workers should be trained to recognize pest damage, and to report disease conditions to IPM specialists.
All production crops should be thoroughly scouted at least once per week by skilled personnel. Pest maps are used to detail the identity and intensity of all pest populations so that biological releases and other treatments can be effectively targeted.
Pest pressures are usually scored on a well-defined 1-5 severity ratio based on plant damage, and visible pest presence.
Pest maps are posted in production areas, where they are visible to all personnel, and daily crop work proceeds from areas of lowest to highest pest pressure to limit human vectoring of pests and pathogens.
When a new or unknown pest pressure emerges, it is important to quickly diagnose and identify the problem.
5) Biological controls:
Releasing insect and mite predators into crops are one of the most efficient ways to control herbivore pests without the use of chemical pesticides.
Biological controls are commercially available in various formats based on their lifecycle, and distribution requirements. Pests have few defenses to these natural enemies.
Following transplant, beneficial nematodes can be watered in, and Hypoaspis mites (Strateolaelaps scimitus) broadcast on the soil surface in a bulk format. These biocontrol agents are great at managing fungus gnats, thrips, and other pests, at their larval stages within the plant rhizosphere, or root zone.
These targeted pests may not cause direct economic damage in Cannabis but can serve as vectors for other pathogens.
Slow-release sachets containing generalist predators such as Neoseiulus californicas, and Amblysius swirskii, provide a continuous and efficient release of predators once the canopy has closed.
These sachets contain predators at various life stages which emerge gradually over a period of several weeks.
When plants enter the flowering stage, bulk carriers can no longer be broadcast on foliage due to the risk of flower contamination. Small boxes or cups can be hung in the trellis to contain these bulk predator releases.
Deployment of biological predators requires active management and assessment. The timing, species, and method of release will vary depending on the specifics of the environmental niche they are deployed into.
Issues of intraguild, and non-target predation, and the life cycle, climate, and feeding characteristics of biocontrols and targeted pests must all be carefully considered and monitored.
Your beneficial insect supplier can provide detailed information as to treatments that are most likely to be effective in your area and may visit your cultivation facility to provide site specific recommendations.
For outdoor cultivators, the release of beneficial bios can be un-economical and impractical if appropriate habitat is not available. It is often more efficient to take an ecological approach, and optimize conditions for the establishment of indigenous predators through companion planting.
6) Chemical Controls:
Responsible use of Pest Control Products (PCPs) is of critical importance for cannabis cultivators and consumers. Smokable flowers cannot be rinsed before use, and some chemical compounds become more hazardous to humans when combusted. These factors render many chemical controls used in other crops inappropriate for use on Cannabis.
It is your responsibility to ensure that only pesticides that have been registered for use on Cannabis in your jurisdiction are applied to your crop. A pesticide label is a legal document, and all requirements must be followed to ensure safety of product, and personnel.
Spray applications also have a plant photosynthetic cost. When overapplied, sprays can form a residue on leaf surfaces, limiting light capture and clogging stomata.
Horticultural Oils and Soaps can effectively knockdown a broad range of Cannabis pests. These products are also detrimental to many Biocontrol species. Horticultural oils should never be used in conjunction with Sulphur due to plant toxicity issues.
Effective application of sprayed Pest Control Products (PCPs) requires trained personnel and appropriate equipment. Factors including droplet size, air movement, and canopy penetration will determine the success of these treatments.
7) Climate Control:
Successful cultivation requires climate conditions that are beneficial to plant performance without favoring pest and pathogen establishment.
Within Controlled Environmental Agriculture (CEA) facilities, airflow, humidity, and temperature must be managed to suppress pathogens and pests, and to promote predator and bioprotectant viability.
Efficient airflow equalizes the grow climate and eliminates turbulence and stagnant air conditions which favor establishment of Powdery Mildew disease. Airflow enables Sulfur vaporization and spray operations to efficiently coat the crop and benefits photosynthetic efficiency.
As cannabis flowers develop, spray operations are no longer indicated. Some products are approved to spray in late flower, but spraying flowering plants can cause elevated humidity within the flowers, increasing the possibility of Botrytis establishment.
In the final few weeks of flower, climate management is one of the few tools available to limit the spread of pathogens, and climate management strategy shifts from optimization of photosynthesis to minimization of disease.
8) Mechanical Controls:
Mechanical pest controls include canopy management, physical barriers, and pest removal.
Regular pruning improves air movement through the foliage and allows for optimal penetration of spray and UVC light treatments. The use of geotextile or plastic covers on growing media can greatly reduce fungus gnat populations which often explode 6-10 days post-transplant.
Sticky cards are used to assess pest pressures and sometimes to reduce them.
Outdoor cultivators often rely on physical barriers to exclude pests including ungulates, rodents, and teenagers.
Slugs can devastate young seedlings but can be effectively curtailed with copper barriers.
In addition to suppressing fungal pathogens, UVC light treatments during late flower help to minimize the microbial counts prior to the flower entering post-harvest processing.
Management of pest pressures is an existential challenge for cannabis cultivators. Production of cannabis in all environments must be carefully monitored to provide a safe and compliant product with limited chemical interventions.
An intelligent Integrated Pest Management Program is critical to this outcome.