Efficacy of Instrata™ 3.61E at rates of 0.54, 0.74, and 1.11 g ai·liter−1 was compared with recommended rates of the its component fungicides Daconil Ultrex 82.5WDG (chlorothalonil), Banner MAXX 1.3MEC (propiconazole), and Medallion 50W (fludioxonil) as well as Eagle 40W, Heritage 50WDG, and 3336 4.5F fungicide standards for the control of Cercospora leaf spot (Cercospora lythracearum) on field grown ‘Byer's Wonderful White’ crapemyrtle (Lagerstroemia indica) in 2007 and 2008. Efficacy of Instrata 3.61E for the control of Cercospora leaf spot on crapemyrtle was significantly impacted by application rate. Cercospora leaf spot intensity and defoliation AUDPC values as well as final disease ratings usually were lower for the 1.11 compared with the 0.54 g ai·liter−1 rates of Instrata 3.61E, while those of the 0.74 g ai·liter−1 rate were intermediate. The 1.11 g ai·liter−1 but not lower rates of Instrata 3.61E gave superior Cercospora leaf spot control in both study years when compared with the Daconil Ultrex 82.5WDG, Banner MAAX 1.3MEC, and Medallion 50W component fungicides with the two former fungicides providing some control in one of two years and the latter failing to reduce disease intensity or defoliation. Eagle 40W, Heritage 50WDG, and 3336 4.5F proved equally effective as the 1.11 g ai·liter−1 rate of Instrata 3.61E in controlling Cercospora leaf spot in 2007 but only Eagle 40W gave comparable disease control in 2008, while Heritage 50WDG and 3336 4.5F were generally less efficacious than all rates of Instrata 3.61E. In one of two years, better disease control was obtained with Eagle 40W when compared with the 3336 4.5F and Heritage 50WDG standards. Overall, efficacy of the 1.11 g ai·liter−1 rate of Instrata 3.61E for the control of Cercospora leaf spot on crapemyrtle was superior to not only the label rate of each component fungicide but also to the fungicide standards in one of two study years.