Spraying of soap solution or soap foam on the plants has some effects in controlling aphids, whiteflies and leaf mites. However, the extent of its use is limited because when solid form of sodium-based soap is dissolved in the aqueous solution, it is difficult to adjust the appropriate ratio. Moreover, if the sodium-based soap solution gets into the soil and is absorbed by a plant’s roots, it could damage the root system and affect the plant growth. To effectively control small-size pests, TARI scientists have developed an easy- and safe-to-use plant protection formulation of agricultural soap. The agricultural soapy liquid at 1-2% is adequate to control aphids and leaf mites. This agricultural soap works only on direct contact with the pests, and its fatty acids disrupt the structure and permeability of the cell membrane of soft-bodied pests. The cell contents then leak from the damaged cells, and the pest quickly dies. This formulation does not act systematically and does not penetrate plant tissues, has no harm on non-target insects, and can be easily decomposed by the environment. Thus it is a safer means of controlling small-size pests.