Spider Mite Host Plants
Overview
Two-spotted spider mite (Tetranychus urticae) has one of the broadest host ranges of any important horticultural pest.
It can affect:
- protected vegetables
- soft fruit
- ornamentals
- herbs
- nursery crops
- outdoor fruit
- field vegetables
- weeds surrounding production areas
Risk is usually highest where host plants are warm, dry, stressed or poorly monitored.
Major protected-crop hosts
Fruiting vegetables
Typical symptoms include:
- pale stippling
- leaf bronzing
- lower-leaf decline
- webbing
- reduced crop vigour
Soft-fruit hosts
In soft fruit, early colonies often begin on older or lower leaves before spreading into the productive canopy.
Ornamental hosts
Even light stippling or webbing can make ornamental plants unmarketable.
Herbs and edible crops
Herbs and edible foliage crops may suffer rapid quality loss because visible leaf damage directly reduces marketability.
Tree-fruit and perennial hosts
Other spider-mite species may also occur on perennial fruit, so species identification can be useful.
See:
Crop symptoms
| Crop group | Typical symptoms |
|---|---|
| Cucurbits | Speckling, bronzing, rapid leaf decline |
| Solanaceous crops | Lower-leaf hotspots, bronzing and webbing |
| Strawberries | Stippling, reduced leaf function and hotspot spread |
| Soft fruit | Lower-canopy colonies and stress-related outbreaks |
| Ornamentals | Cosmetic stippling, bronzing and webbing |
| Herbs | Visible leaf damage and reduced saleable quality |
| Nursery crops | Hidden carryover populations and repeated outbreaks |
High-risk crop conditions
Host plants are more vulnerable where there is:
- uneven irrigation
- restricted rooting
- high fruit load
- low humidity
- dusty foliage
- hot glasshouse edges
- recent pesticide disruption
- crop carryover
- old infested plant material
- poor access for monitoring
Weed and reservoir hosts
Spider mites may persist on:
- weeds beneath benches
- weeds around tunnels
- volunteer crop plants
- discarded crop material
- old stock plants
- ornamentals near production areas
Reservoir plants can allow mites to re-enter clean crops after treatment or crop change.
Monitoring by host plant
Inspect:
- lower leaves
- leaf undersides
- hot crop edges
- irrigation problem areas
- dusty plants
- previously affected rows
- incoming plants
- weeds and crop residues
Record both pest mites and predatory mites.
Reducing host-plant risk
Useful actions include:
- maintaining even irrigation
- reducing plant stress
- removing heavily infested leaves where practical
- controlling weeds
- cleaning crop debris
- introducing preventative predators early
- treating active hotspots rapidly
- avoiding unnecessary broad-spectrum pesticides
- checking clothing and tools after working in hotspots