We tested the toxicity of 34 pesticides on the adult ladybird beetle Serangium japonicum Chapin, a predator of the tea spiny whitefly Aleurocanthus camelliae Kanmiya and Kasai in tea fields by contact method using tea leaves. Organophosphate insecticides—acephate and methidathion and neonicotinoid insecticides—clothianidin, methomyl, bifenthrin, cyantraniliprole, spinetoram, and cartap were moderately or seriously harmful. Silafluofen, chlorantraniliprole, and spinosad were slightly harmful. Methoxyfenozide, lufenuron, abamectin, emamectin benzoate, milbemectin, flubendiamide, ethiprole, chlorfenapyr, pyrifluquinazon, diafenthiuron, spiromesifen, tolfenpyrad, fenpyroximate·buprofezin mixer, etoxazole·pyrimidifen mixer, machine oil, and some fungicides were harmless.