Two-spotted spider mites are the leading arthropod pest of indoor and greenhouse cannabis, and they move from leaf undersides onto flower. During flowering, scout twice weekly and act at the first stippling, before webbing forms. Remove heavily webbed leaves, spray both leaf surfaces with a miticide designed for in-season use on sensitive crops, and avoid peak-sun applications.
Common crops affected
Why do spider mites matter in cannabis?
By draining cells they cut photosynthesis and yield, and infestations flare fast in hot, dry conditions and after broad-spectrum sprays kill predators. Their webbing protects them, so early control matters.
When should you act on spider mites?
Scout twice weekly; act at first stippling, before webbing. Pressure peaks in warm, dry, dense canopies.
How do you spot spider mites on cannabis?
- Fine stippling and pale speckling on leaf tops
- Webbing on undersides and around buds
- Bronzing and curling of stressed leaves
- Mites and eggs under a loupe on undersides
How do you manage spider mites in cannabis?
- Reduce dust and heat stress where practical; protect predatory mites.
- Remove and destroy heavily webbed leaves.
- Spray Spider Mite Control on both leaf surfaces at 1:500; repeat every 3–5 days.
- Avoid peak-sun applications to prevent oil phytotoxicity.
Which Vegalab program is recommended for spider mites?
Spider Mite Control · encapsulated contact-and-residual miticide for sensitive flowering crops, zero PHI and zero REI.
| Role | Product | Use |
|---|---|---|
| Primary control | Spider Mite Control | Contact miticide; suffocates mites & deactivates eggs |
| Broader pressure | MultiMite Control | Mixed mite/insect pressure |
| Plant resilience | Armour Boost | Silica for tougher tissue |
Product claims, rates, and availability vary by jurisdiction; always follow the applicable label.
Key takeaways
- Warm, dry rooms let spider mite numbers explode in days.
- Look for fine stippling on leaf tops, webbing on undersides and around buds, and bronzed, curling leaves.
- Scout twice weekly and act at the first stippling, before webbing.
- Broad-spectrum sprays that kill predators make infestations flare, so protect predatory mites.
- Spray both leaf surfaces and avoid peak-sun applications to prevent oil phytotoxicity.