Papaya rust is mainly caused by basidiospores produced by papaya after spring rain, which spread with wind and rain. This is an important stage from germination to young fruit formation in papaya tree, and spores will invade from epidermal cells. Then after an incubation period of 6 ~ 10 days, orange spots will appear on the leaves, and after 20 ~ 25 days, the above-mentioned hairs will appear and invade the tender leaves and new shoots of the main pine and cypress.