Poly(lactic acid)(PLA)/cellulose nanocrystal nanocomposite fibers were prepared by electrospinning at elevated temperature. Columbia Blue, a nonionic hydrophobic dye with a molecular weight and partition coefficient that mimics a systemic agrichemical, was incorporated into the fibers as a model compound. The release of Columbia Blue into water displayed little burst release. Diffusion-controlled release of Columbia Blue was significantly influenced by the hydrophobicity of the electrospun PLA nanocomposite fibers and followed Fickian diffusion kinetics. The release of Columbia Blue by degradation-controlled mechanism followed zero-order, time-independent Case II kinetics (n = 1.0). Increasing cellulose nanocrystal content in the fibers increased the fiber degradation rate and the Columbia Blue release rate. The plasticizing effect of Columbia Blue on the thermal properties of the electrospun nanocomposite fibers showed the miscibility of Columbia Blue inside the electrospun nanocomposite fibers. A greenhouse trial confirmed the anticipated trends of higher pesticide dosage causing higher whitefly mortality percentage. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2012