Mites: Spider, Russet & Broad
The three mites that end grows — how to tell webbing spider mites from invisible russet mites from meristem-attacking broad mites, the magnification each demands, and the predators that hold each one.
8 min read
Mites cause more total-loss cannabis crops than any other pest, and the three that matter attack in three different places with three different tells. Get the ID right and the response is straightforward; get it wrong and you release the wrong predator while the population explodes. The fastest triage question: is there webbing, is the damage on old growth or new growth, and can you see the mite with a loupe?
| Mite | Signature | Location | Magnification to ID | Threshold |
|---|---|---|---|---|
| Two-spotted spider mite | Pale stippling on upper surface → bronzing → fine silk webbing; loves hot & dry | Undersides, lower canopy first, migrates up | 10–14× loupe (0.4–0.5 mm, two dark spots) | Act on first colony/webbing |
| Hemp russet mite | Overall bronzing/'russetting', brittle leaves, upward edge curl, NO webbing | Undersides, lower canopy first | 80–100× scope (<0.2 mm, invisible to loupe) | Act once confirmed (damage precedes visible mites) |
| Broad mite | NEW growth twisted, glossy 'wet-plastic', taco-curled; corky undersides | Apical meristem / top of plant | 60–100× scope (~0.2 mm, translucent) | Act on first distorted new growth |
The rest of this lesson is for members
Unlock every department, SOP, calculator, and setpoint table — plus Leaf, your AI consultant, and interactive diagnostics.
- All 11 departments
- Coco & rockwool tracks
- The full SOP library
- Leaf AI consultant
Unlock full access membership from $490/yr · or own it for life