Previous research conducted in Costa Rica determined that Trichoderma ovalisporum, when applied in a water-in-oil emulsion to Theobroma cacao pods, had less Moniliophthora roreri (frosty pod rot) than in water. The current research was conducted to determine why bio-control agents when applied to cacao pods were more effective in a water-in-oil emulsion than water for controlling frosty pod rot. The experiments were conducted in Ecuador in 2011 and 2012. Two formulations were used: water-in-oil emulsion and water. Water-sensitive cards were attached to the lower branches of the cacao trees. There were four trees per treatment and six cards per tree. One hundred and eighty ml of formulation were applied to each tree with a Stihl SR 420 backpack mist-blower. The cards underwent droplet analysis with the DepositScan software package. Droplet analysis determined that the increased efficacy of water-in-oil emulsion was the result of the micro-environment advantage of the water-in-oil emulsion.