A control agent exhibiting an excellent control effect on Mesostigmata mites and having as effective components thereof: a specific quinoline derivative compound such as 8-fluoro-2, 3-dimethyl-6-(1,1-dimethylethyl)-4-(methylcarbonyl) oxyquinoline； azoxystrobin； picoxystrobin； pyraclostrobin； kersoxim methyl； trifloxystrobin； metominostrobin； olisastrobin； famoxadone； fluoxastrobin； pyribencarb； cyazofamid； amisulbrom； flutolanil； mepronil； isofetamid； fluopyram； carboxin； thifluzamide； fluxapyroxad； furametpyr； penflufen； penthiopyrad； boscalid； diflumetorim； fluazinam； ferimzone； fenpyroximate； or an acid addition salt of these compounds.<；i/>； <；i/>；.Un agente de control que comprende, como un ingrediente activo, un compuesto derivado de quinolina específico tal como 8-fluoro-2,3-dimetil-6-(1,1-dimetiletil)-4-(metilcarbonil)oxiquin olina, azoxistrobin, picoxistrobin, piraclostrobin, kresoxim-metilo, trifloxistrobin, metominostrobin, orisastrobin, famoxadona, fluoxastrobin, piribencarb, ciazofamid, amisulbrom, flutolanil, mepronil, isofetamid, fluopiram, carboxin, tifluzamida, fluxapiroxad, furametpir, penflufen, pentiopirad, boscalid, diflumetorim, fluazinam, ferimzona, fenpiroximato, o una sal de adición de ácido de cualquiera de estos compuestos muestra un excelente efecto de control en ácaros Mesostigmata.
