During hot or dry periods sporulation ceases but will often restart with a return to cool moist conditions. Urediniospores are the single source of inoculum. Inoculum often comes from volunteer wheat plants and dormant infections that initiate or continue sporulation when conditions become favorable. Inoculum may move from nearby fields that were sown earlier or from later maturing fields. Free water on the leaves and temperatures of 0 to 25 C are required for spore germination.
Penetration is through the stomata.
The latent period may vary from 11 days with mean daily temperatures of 15 C, to perhaps 180 days with near freezing temperatures. Hot summers and dry seasons are most threatening to stripe rust survival. Survival between crop seasons is by dormant mycelium and uredinia on infected volunteer wheat in most areas. In mountainous tropical and subtropical areas stripe rust can survive by moving up and down the mountain on seeded wheat. Infected grasses probably play no role in survival in most of the world.