Let's talk about Thrips
Many things can negatively affect cannabis including environmental conditions, poor genetics, viruses, and pests. Pests can be a huge nuisance and contribute to additional labor and costs in an effort to eradicate them.
Many pests can affect cannabis crops, including spider mites, aphids, fungus gnats, and thrips. There are a few kinds of thrips that like to feed on cannabis.
These include greenhouse thrips (_Heliothrips haemorrhoidalis), western flower thrips (Frankliniella occidentalis), and onion thrips (Thrips tabaci).
Many cultivators have battled thrips at some point in their grows. But what exactly are thrips? Thrips are small, oval, typically tan with piercing and sucking, cone-shaped mouthparts, which they use to feed on leaves. In particular, they happen to love cannabis leaves. They leave behind silver or bronze spots where the leaves had been bitten. Left untreated, the leaves may become necrotic. The adults develop narrow wings and can move long distances with the help of wind or being spread by employees throughout facilities. Thrips have been shown to diminish product quality and yields, posing an economic threat to cannabis cultivators.
The thrip life cycle is similar to that of other species in the family Thripidae and includes six stages of life. It begins with the egg, which takes roughly six days to hatch. Once it hatches, it enters two larval instar stages, followed by a pre-pupa, a pupal instar, and finally, the adult insect. This full process takes around sixteen days. Prior to the females laying eggs, the female thrip will make an opening in the plant tissue and then deposit eggs into plant material using a saw-like ovipositor.
Prevention
It is best to try to prevent infestations from happening in the first place. This can prevent minor issues from progressing into larger infestations that can be much more costly and labor intensive to treat.
Prevention can include changing from outside clothes and shoes before entering the facility, quarantining any new plant material before bringing it into the facility, and preventative IPM. In addition to these prevention measures, routine scouting is also crucial.
The easiest way to do this is by incorporating consistent and automated scouting for damage through systems like the Neatleaf Spyder.
Unfortunately, due to the thigmotactic nature of the thrip lifestyle, it is highly resistant to direct exposure to insecticides.
Thrips also rapidly build up an immunity to pesticides, which may make them even more resilient to treatment.
Effective IPM programs for thrips require using multiple methods of control at various stages of their lifecycle, including chemical, biological, and cultural control. Species in the genus Orius, which are predatory insects, have been found to suppress populations of thrips and the predatory mite Cucumeris.
In addition to these natural thrip enemies, pesticides such as Pyrethrins and Azadirachtins can efficiently remove these pests. Always check with local regulations to ensure what you use in your facility is compliant and safe for the current stage in the growth cycle.
In the ever-evolving landscape of cannabis cultivation, sharing knowledge and experiences is invaluable. We're curious to hear from fellow growers: What are some of your biggest challenges in your grow room? What routines or products have you found effective in managing thrips or other pests in your grow room?
Whether it's a preferred pesticide or a unique IPM strategy, your insights could benefit others facing similar challenges!
References
Biology and Ecology of the Western Flower Thrips (Thysanoptera: Thripidae): The Making of a Pest
Invasion Biology, Ecology, and Management of Western Flower Thrips
Written by Allison Zervopoulos
Plant Scientist, Neatleaf
Allison Zervopoulos has over 16 years of experience in the cannabis industry, with a specialized focus on cultivation. With a background in plant science, Allison excels at optimizing practices to maximize yields and ensure high quality. As a successful startup leader and strategic consultant, Allison Zervopoulos brings a wealth of knowledge to cannabis ventures. She is driven by innovation, professionalism, and integrity and is dedicated to advancing the industry.