Ground and infrared aerial surveys conducted monthly at approximately the same time in 6 citrus groves showed that infrared aerial photography can be used to detect progressive buildup of Coccus hesperidum L. Also, random photographs of other groves showed that developing infestations of the scales can be detected with this remote-sensing technique. Infrared color photographs taken from heights of 2000 and 5000 feet demonstrated the changes brought about in citrus foliage by this pest. The effect of sooty mold fungus, Capnodium citri Berk. & Desm., caused by brown soft scale, on the reflectance characteristics of citrus leaves was measured.