Pyrethrin
A fast-acting natural insecticide derived from chrysanthemum flowers that disrupts insect nerve function on contact.
What it is
Pyrethrins are naturally occurring insecticidal compounds extracted from the flowers of Tanacetum cinerariifolium, the Dalmatian chrysanthemum. They are among the oldest plant-derived insecticides and are approved for certified organic use. They break down rapidly in sunlight and within 24 - 48 hours in the environment.
What it does
Pyrethrins bind to sodium channels in insect nerve membranes, causing paralysis and death by overwhelming the nervous system. They act within minutes of contact. Because they degrade rapidly, they do not accumulate in soil or plant tissue, but this also means they have no lasting residual protection.
When to use
Reserve pyrethrin for established pest infestations where gentler methods have been insufficient. Apply in the evening to reduce direct exposure to pollinators and to slow UV degradation. Most effective as a knockdown spray when pest numbers are high and quick action is needed.
When not to use
Never apply directly to open flowers or areas where pollinators are actively foraging, as pyrethrins are highly toxic to bees and other beneficial insects. Avoid applying near water as they are very toxic to fish and aquatic invertebrates. Do not use as a routine preventive - reserve for targeted interventions only.
How to apply
- 1
Read and follow the concentration instructions on the chosen certified-organic pyrethrin product label exactly.
- 2
Apply in the evening after bee and pollinator activity has ceased for the day.
- 3
Spray all affected plant surfaces thoroughly, focusing on the undersides of leaves and dense foliage where pests congregate.
- 4
Avoid spraying near open water, ponds, or drainage channels.
- 5
Monitor plants after 24 hours. A single well-timed application often provides sufficient knockdown; repeat only if significant pest pressure persists.
Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.