Despite integrated pest management (IPM) practices being taught and researched for over six decades, farmers' adoption of such practices has been limited. Integrated pest management is a comprehensive management approach that utilizes multiple strategies to keep pest populations below economic threshold levels, protecting non-target organisms, safeguarding the environment, and utilizing tactics to prevent pest populations from developing resistance. In this chapter, we review extension theories and methodologies and identify useful resources to aid in the diffusion of IPM information to increase the adoption of IPM practices in horticultural crops. We discuss Rogers (1963) 'Diffusion of Innovation Theory' and research related to the diffusion of IPM around the globe. We also discuss how the use of logic models can improve the planning and efficiency of extension programs. Finally, we discuss E-extension and virtual communication and outline possible barriers to the adoption of IPM innovations and how they can be overcome.