Precision Fumigation is defined as ‘optimizing fumigant use to maximize efficiency and minimize risk’. To achieve Precision Fumigation of flour mills requires the close cooperation of the miller and the fumigator to ensure operational safety and efficacy is achieved with minimal disruption to production schedules. It is important that the SPIs present in the mill are correctly identified and the temperature at the site of insect activity is known. The volume of the site to be fumigated should be accurately calculated and an estimate of the gas retention potential of the site made. To help the fumigator considers various scenarios and to complete a Precision Fumigation, Dow Agro Sciences has developed the Perfume Fumiguide™ (a PC-based software program). By varying fumigation factors: target pest, life stage, temperature, exposure time and gas retention time job-specific target dosages (concentration x time products or Ctps) and amounts of sulfuric fluoride can be established. An optimal fumigation plan can then be selected from the various fumigation scenarios considered.