Spinosad - Pests it Manages, Pros & Cons, How to Use

Spinosad is a natural insecticide made by fermenting a soil bacterium. It's especially good on caterpillars and thrips — two of the trickier veggie-patch pests — and it's gentle enough for organic gardens.

Pests it manages:

• Caterpillars (including cabbage white and diamondback moth)
• Thrips
• Leaf miners
• Some beetles

How to use it:

1. Mix to the label.
2. Spray in the evening — spinosad is hardest on bees while still wet, and safe once dry.
3. Cover both sides of the leaves where caterpillars feed.
4. Reapply after heavy rain, or every couple of weeks while pests are active.

The good:

• Excellent on caterpillars and thrips, which many gentle sprays miss.
• Low toxicity to people, pets and (once dry) bees.
• Accepted for organic growing.

The catch:

• Toxic to bees while wet — always spray in the evening, never on open flowers.
• Can be dearer than other sprays.
• Rotate it with other controls so pests don't build resistance.

Spinosad is a great safe option when caterpillars are chewing through your brassicas. For the bigger picture, see our guide to managing pests safely.

Plan your patch: our free planting calendar shows what to plant now where you live. Ready to grow? Browse our raised garden beds or build your own with the garden bed builder.

Image: Sam Fraser-Smith, CC BY 2.0, via Wikimedia Commons.