Puccinia species (cereal rusts) produce dikaryotic urediniospores which are thick-walled, pigmented, resistant to UV radiation and desiccation, and aerodynamically suited for long-distance atmospheric transport.
In India, Dr. K.C. Mehta demonstrated that urediniospores travel thousands of kilometers along the 'Puccinia path'—carried by low-level wind currents from southern foci (Nilgiri and Palani hills) to the northern Indo-Gangetic plains.
By contrast, Pythium and Phytophthora produce short-lived zoospores or sporangia requiring high moisture, and Magnaporthe conidia are typically dispersed locally over shorter distances by rain splash and dew.