Things to know before using insecticides
Do your homework and make wise choices. All insecticides should be used only when necessary and plant based compounds are safer for people, pets and the environment than chemical ones.
Sprays of a mild soapy water solution are often an effective first defense and should be repeated weekly until infestation is gone. Spray early in the day so the plant can dry before evening. Be sure to spray stems, flowers, and both the top and undersides of the leaves. You can apply a second spray of clear water after an hour or two if you feel the plant may be very sensitive to soaps. Use this spray if the temperature is less than 90°F (32°C) and more than 40°F (4°C) or leaf damage may occur. If it is too hot or cold you can use a spray of clear water to knock insects off and wait for a better day. You can also use your bathroom shower. Do not spray a plant in direct sunlight as water on the leaves may burn the leaf.
You can purchase these sprays or follow this recipe for homemade mild soapy water solution.
There are some plants whose leaves are sensitive to soaps in which case you will see yellow or brown spots on the leaves after application and you should not repeat the procedure. You can test a small area and check for any unwanted signs 24 hours later if unsure. Crown of thorns, Jade plants and Gardenias are some examples. Some ferns, palms and succulents may also be sensitive.