Thrips are small winged, long bodied insects your plant may attract if it has a summer vacation outside, in a greenhouse or sometimes in your home. Color varies between species being yellow, green to light brown and feed mainly on leaves. Other varieties are dark brown to black. You may see them jump when disturbed. They will burrow into flower buds to feed where you will never see them (you may see white spots on flowers) so if you know you have an infestation and are going to begin treatment it is best to remove all flower buds at this time. Some species inject a digestive enzyme which leaves a distinctive silvery or bronze scarring on the surfaces of the stems or leaves where the thrips feed. Infested leaves become curled or distorted, with silver-gray scars. Thrips can transmit a wilt virus to many different ornamentals and vegetables.
Control: Isolate infected plant(s) and cover any tables or carpet, etc. that may receive any over-spray if using soap or oil sprays.
Sprays of a mild soapy water solution are effective and should be repeated weekly until infestation is gone. There are some plants whose leaves are sensitive to soaps in which case you will see brown spots on the leaves after application and you should not repeat the procedure. Crown of thorns, Jade plants and Gardenias are some examples. Some ferns, palms and succulents may also be sensitive. You can test a small area first if unsure.
Use a systemic insecticide only if necessary. The roots absorb the insecticide and the insect will feed on it along with the sap. Always read instructions on purchased products before use and be certain it is appropriate for the plant and the insect you have.