Insecticidal soaps & neem oils are effective on soft-bodied insects and arthropods; this includes aphids, mealybugs, spider mites, thrips, jumping plant lice, scale insects, whiteflies, and sawfly larvae. It is also often used for caterpillars and leafhoppers, however these larger-bodied insects may need more than soap to eliminate them. Soaps will kill predatory mites that may help control spider mites.
Because of their soft bodies, aphid-eating larvae of ladybugs, lacewing, and hoverflies may also parish when insecticidal soaps are applied. According to one study, a single soap application killed about 15% of lacewing and ladybug larvae, and about 65% of predatory mites.
They are also safe to use around pets and children. It can be used in an aquaponic system as long as it is used sparingly; ie the spray should not drip off the leaves and into the media.
Neem oils eliminate the insect by suffocating it. Be careful to follow the instructions exactly to prevent burning or scalding plants. It is best to test your plants by applying the neem oil to a small section and waiting 24 hours to see if it burns or scalds the leaves.
Soaps and oils kill on contact and need to be reapplied two or three times to impact an infestation.
Both of these solutions work best if the temperature is less than 90 degrees. Hotter temperatures will also encourage browning or of the wilting leaves.