Streaking of the colors in tulip petals is known as flower “breaking.” Many cultivars are available with interesting color breaks. Some of you may have heard that flower breaking can also be caused by virus. How do you know you have a tulip with flower break as a result of plant breeding as opposed to one with a viral infection?
Tulips are host to many viruses. They may succumb to arabis mosaic nepovirus, tobacco rattle tobravirus, tomato black ring nepovirus, tomato bush stunt tombusvirus, tulip band-breaking potyvirus, tulipbreaking potyvirus, tulip chlorotic blotch potyvirus, tulip halo necrosis virus, and tulip X potexvirus. Those causing flower breaking include tulip X, tulip chlorotic blotch, and tulip breaking virus. These viruses also cause leaf symptoms, including chlorotic or gray–brown streaking, blotching, or leaf chlorosis. The intensity of the symptoms may vary with the tulip variety, the degree of infection, and possibly growing conditions. So if the virus is causing flower break, you should also see symptoms on the leaves. Aphids spread the tulip breaking potyvirus. Tulip chlorotic blotch is spread mechanically. For detailed information on viruses by host, visit http://image.fs.uidaho.edu/vide/famindex.htm.
Tulip breaking is most common in late-flowering cultivars. Pink, purple, and red tulips are more commonly affected, while white and yellow cultivars are not affected with this virus.
Tulip break viruses are spread by aphids, but insecticides are not very effective in disease control. Because viruses are with a plant for life, it is best to remove infected bulbs. Interestingly, lilies may also host these viruses without noticeable symptoms. Try not to plant lilies and tulips together.
If you have purchased tulips advertised as variegated types, you have most likely bought a cultivar that was bred for these qualities. The streaks, stripes, and blotches should be similar in all plants, not hit and miss as with virus-infected tissue. In addition, the bulbs of infected plants are small and plants do not grow vigorously.
If you fear you have a tulip infected with virus, there are some ELISA tests for specific viruses or virus groups. Visit the testing services available at companies such as Agdia, Inc., in Elkhardt, Indiana. Fees are generally high for the first sample and much less for each additional sample of the same test.