If the plants are older at infection, symptom development is slower. Symptoms on a middle leaf of a mature plant showing spots in various stages of development and purpling along the leaf margin. Even with just a few spots, some spots form streaks or linear arrays. Spots never have margins or distinctive centers, they may be yellow or nearly white or there may be yellow, white and dead spots mixed on the same leaf. Spots or leaf margins are never sunken or water soaked.
Necrotic spots are a uniform light brown to tan.
Note that the symptoms are worse on the lower leaves and progressively less severe up the plant. In this genotype the symptoms are expressed as definite sectors or streaks of spots. In some genotypes the sectors are very sharply defined by the vascular bundles and may be very uniform in color. The color of the sectors may vary from light green to yellow to nearly white. This is an electron micrograph of an HPV infected wheat cell.