Spider mites on roses
On roses, spider mites stipple or bleach the leaves, which may dry up and fall. High numbers follow dry, dusty conditions and sprays of carbaryl or pyrethroids (UC IPM). Water the roses well, hose the leaves, undersides too, and keep the dust down. To release predators on a heavy infestation, first bring the mites down with a soap spray; UC IPM puts the need at one predator per ten spider mites. N. californicus copes with heat and dry air better than Phytoseiulus (Cornell).
At a glance
- Damage
- Pale stippling, bronzing, webbing under leaves
- Type
- Sap feeding
- Settings
- Under glass, Field, Garden, Indoors
- Threshold
- At the first mites found — no numeric threshold
- Release
- Neoseiulus californicus
- Rate
- 1–4 per plant, every two weeks, 2–3 times (Arbico; Cornell gives the same per-plant figure)
How to confirm it
Confirm with a 10× hand lens on the leaf underside: oval yellowish-green mites with a dark blotch on each side, round translucent eggs, white cast skins and fine webbing. Tap a leaf over white paper and they walk off.
Identification, lifecycle, degree days and every control option are on the full Two-spotted spider mite profile. Not sure it is this pest? Answer four questions about the damage.
Work it out
How many do I need?
Carries Neoseiulus californicus and roses through so nothing is re-entered. Open the calculator →