In many natural communities communication between plants and other organisms below ground drives community dynamics. This communication is primarily through the release and detection of infochemicals, which must traverse the soil matrix to be effective. In this opinion article, we propose the Network Enhanced Bioactive Zone (NEBaZ) model, which posits that common mycorrhizal networks (CMNs) increase the bioactive zones of infochemicals by serving as superhighways directly connecting plants below ground. Here we argue that infochemical transport via CMNs allows for systemic defense signaling across plant populations and directed allelochemical delivery to target plants. Plant-animal interactions may also be facilitated by CMNs, suggesting that these fungal networks may be crucial components of many natural ecosystems.