Plants with HPV and WSMV typically occur next to volunteer wheat. Symptoms of doubly-infected plants are severe chlorosis, strong mosaic, severe stunting, and rapid plant death. The rapid death of infected plants was a serious hindrance to work on the virus. Occasionally, singly-infected plants have been found. Symptoms of pure HPV infection are quite variable.
Some leaves have green and yellow stripes at the leaf tips similar to wheat streak mosaic.
Others have yellow spots. Still others have green islands on a light green background and look similar to soilborne mosaic. All of these types of leaves can occur on the same plant. We haven't yet found any differences between varieties in symptom expression. Dallas Seifers and Tom Harvey recently discovered that HPV was transmitted by the wheat curl mite, the same vector that carries wheat streak mosaic virus.