Flower Breaking

Abnormally streaked or striped flower petals are a symptom of flower breaking.  The problem is common on tulips, gladiolus, and lilies.  It is caused by viruses that may also produce mosaic, stunting, and other symptoms.  The virus is spread by insects (especially aphids); by diseased stock; and by the handling of a healthy plant after working with a diseased one.  The health of the plant is not frequently damaged, though appearance is affected.  Plant disease-free stock, and control insects and weeds.  Destroy infected plants.