In Cannabis, there are currently few labeled chemicals for indoor use. Of those that are labeled for use, horticultural oils and biologics make up most of the options. Proper use of horticulture oils generally requires a whole plant drench and depending on grow room conditions and choice of spray, they can result in phototoxicity and injury to plants. Additionally, while horticulture oils are labeled for use in Cannabis, how long they persist on the plant and how that affects the finished product is understudied.
So what’s a grower to do? Incorporate an IPM mindset!
What is IPM exactly?
IPM is about managing pests, not eradicating them. The basis of IPM is to keep the damage caused by pests below a threshold where you will suffer economic loss. This is accomplished using cultural techniques such as plant quarantining, establishing barriers to entry, or the use of pest resistant genotypes; using physical removal methods and having a comprehensive scouting protocol; and using biological means such as introducing pest predators or parasites.
Most insect pests make their way into indoor facilities either by adhering to clothing or shoes or by coming in on infected plants. To minimize the risk of bringing in pests on clothes and shoes, a set of work-only clothes should be kept in the facility.
To minimize the risk of pests coming in on infected plants or supplies, new plants and material should be quarantined initially. If you find infected plants in your grow room, the easiest way to stop the spread is to quarantine them.
Another way to prevent outside pests from entering a grow room is to use insect-exclusion micromesh filters. These fit over open vents and airflows, restricting what can enter. A positive pressure room may also be a method of preventing insects from entering. Depending on the pest of concern, monitoring plants with blue or yellow sticky cards can help with control and are good tools for helping to scout for pests. Using genotypes that are more resistant to pest damage or less prone to yield reductions is another cultural IPM strategy.
Monitoring, prevention, and treatment under IPM
During routine plant care you should be inspecting your plants, both on the top and bottom of leaves, as well as your substrate. If you are growing in a soil based medium, insects may lay eggs on the leaf tissue, but the adults may live primarily in the soil. Understanding the life cycles of insect pests will help you better scout for them.
The physical removal of pests can be time intensive if used as a primary control mechanism, but as a preventative measure is easy to incorporate into existing scouting protocols. Physical removal is unlikely to control large outbreaks but can be an important step in preventing the outbreak. Physical removal of pests will also allow the proper identification of pests. Many extension offices will have entomologists on staff, allowing for proper identification of pests if provided with clear photos or intact specimens.
In situations of a large outbreak, biological control can be a useful tool. Biological control works by introducing another organism that may prey on, parasitize, or infect the target. There are many options in terms of biological control, but many of them are pest specific. Proper identification of pests is therefore imperative for effective biological control. Remember though, biological control reaches maximum effectiveness with repeated applications.
This is just meant to be an overview of IPM. We will be working to update this post and others. Keep an eye out for our series examining specific pests in the coming weeks!
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