Integrated Pest Management Guide

Updated: May 19, 2018




Why IPM?


Pests can wreak havoc in the cannabis garden. Mites, aphids, mildew and mold can quickly destroy an entire harvest. The economic impact is tremendous-- estimated around $600/lb in production costs alone. With so much on the line, it is tempting to “go nuclear” and frequently apply harsh chemical pesticides. Don’t do it!


Reactionary pest management damages plants and creates pesticide-resistant disease. Excessive pesticide applications also pose risk to garden workers, the consumer and environment.


Integrated Pest Management is a common-sense, long-term strategy to deal with pests and disease in the garden. IPM combines multiple strategies to suppress pest populations with minimal pesticide applications. Chemicals are simply one of many coordinated components that provide defense, and offense against pests.


A Holistic Approach


IPM manages the garden ecosystem to be less favorable for pests. It uses prevention, cultural, mechanical and biological methods to disrupt the pest life cycle. IPM makes it difficult for pests to reproduce, find food, water or shelter. IPM action plans coordinate the entire production process to mitigate the economic, health and environmental impacts of pests.


IPM may include responsible use of chemical pesticides, but only when routine monitoring shows that a pest problem exists. Apply insecticides and fungicides at minimal effective dosages and in conjunction with other measures. Overdependence on one chemical method is evolutionary pressure toward pesticide resistance.


Suppression, Not Eradication


The goal of IPM is suppression of pest levels below the threshold of economic damage. Complete eradication of disease is not always the goal of IPM. Zero tolerance policies perversely create pesticide-resistance because only the strong pests survive and reproduce after apocalypse. Better to use multiple non-chemical methods mitigate the onset, duration and intensity of infestation. Pesticide resistance does not develop because IPM does not rely on a single control mechanism.


Know Your Enemy


IPM starts with an understanding of pest life cycles so you can eliminate conditions that favor growth. It’s time to get to know your enemy:

  • How does it reproduce and spread?

  • What are the life stages?

  • What temperature, humidity and pH does it like?

  • What part of the plant does it attack?

  • What are the natural competitors and predators?

Prevention


Prevention is the most essential component of IPM. Further action is not needed if the pest is never allowed to establish itself. Create a garden environment that discourages the life cycle of pests:

  • Quarantine plantstock from other gardens to observe for disease.

  • Shower and change clothes before entering your garden.

  • Seal gaps and maintain positive air pressure for indoor grows.

  • Clear vegetation around outdoor grows.

Monitoring


Pest monitoring identifies small problems before they become big infestations. Routine and standardized methods determine how quickly a problem is spreading and what action is needed. There are two types of monitoring:

  • Passive- A sampling device, such as sticky traps, collects information about pests in the garden.

  • Active- Manual inspection of plants on a regular schedule. Randomized sampling of plants when it is not possible to inspect all plants routinely.

Acceptable Pest Levels and Action Thresholds


An acceptable pest population does not cause significant economic damage to the crop. Action levels define what corrective measures to apply when the population exceeds acceptable levels. Low action thresholds trigger softer tactics, like predator insects. Bigger outbreaks merit more severe treatment, such as chemical pesticides.


Cultural Methods


This is where your style intersects with pest control. Every action has a reaction-- be aware of how your management decisions ripple throughout the garden cycle. For example, over-watering can contribute to root disease and under-watering renders foliage susceptible to insect attack. Cultural methods are preventive and require advance planning.


Physical and Mechanical Methods


Plants can be physically separated and pests can be mechanically removed. Plant quarantine areas are a classic example of physical control-- barriers prevent the further spread of disease. Other examples:

  • Rinsing foliage with water to remove insects and spores.

  • Manually removing diseased foliage.

  • Using sticky traps to catch pests.

  • Keeping plant canopy physically separated slows plant-hopping diseases.

  • Frequently washing and sweeping the grow room.

Biological Controls


The enemy of your enemy is your friend. Pests have predators, competitors, parasites and pathogens all their own. A healthy garden ecosystem is like an immune system for the plant. Probiotic bacteria and fungi attack pests and prevent them from colonizing the plant. Beneficial insects like ladybugs and predator mites eat unwanted insect life. Biological controls work best as a preventative treatment.


Pesticides


Pesticides are a last resort in IPM. Sometimes plants are better left untreated. When necessary, choose the least severe and most targeted pesticide and only apply it to affected areas. Make sure the pesticide you select is approved for use on food crops and apply it at the minimally effective dosage. Never spray blooming cannabis because the chemicals will coat the flowers. Chemical control is not permanent, so it is important to continue with the entire IPM plan.


Many Small Hammers


The efficacy of IPM depends entirely on the attentiveness and proactivity of the gardener. IPM should be a part of every garden task. Manage the environment and create a plant care routine that inhibits pests. When possible, use “many small hammers” to to avoid over-reliance on harsh chemical pesticides. IPM ensures the long-term health and success of your cannabis garden.