PROBLEM TO BE SOLVED: To provide a Coccoidea insect-killing composition for agricultural and horticultural use that has excellent effect on scale insects that are covered in a shell and have low sensitivity particularly in winter (low temperature period).SOLUTION: A Coccoidea insect-killing composition for agricultural and horticultural use contains a water-soluble organic solvent (glycol ether solvent) as a base, and contains neonicotinoid and pyrethroid insecticidal components (particularly clothianidin and fenpropathrin).SELECTED DRAWING: None