An organic pesticide made from fatty acids that kills soft-bodied insects (aphids, whiteflies, spider mites) on contact by disrupting their cell membranes.
In plain terms
Insecticidal soap is a mild, organic pesticide effective against soft-bodied insects. It works on contact; once it dries, it's harmless to other organisms. It doesn't persist in soil or kill beneficial insects. It's ineffective against hard-bodied insects (beetles, scale) and requires repeat applications every 5-7 days if infestations persist.
Why this matters
Insecticidal soap is one of the safest, most effective organic pest controls for soft-bodied insects. It kills pests without disrupting beneficial insects.
In practice
Examples
Aphid infestation treated with insecticidal soap; aphids die within hours of spray; reapply if new aphids appear.
Whitefly spray with soap; kills adults and reduces population; repeat weekly until gone.
Spider mite spray with soap; effective on small mites; large infestations may require multiple sprays.
Early morning application before beneficial insects become active; thorough coverage necessary for contact kill.
Practical applications
Spray in early morning or evening when beneficials are less active.
Spray until foliage drips; thorough coverage necessary for contact kill.
Reapply every 5-7 days if pest population persists.
Mix at label strength; more soap doesn't mean better control, just waste.
Monitor for scale insects and hard-bodied pests that require different treatment.