Distribution
Control of the virus is notoriously difficult. Its distribution is world-wide and had been reported in all temperate regions where tulips are grown; it is particularly common in southern Europe where the aphid vectors are abundant early in the growing season. Virus transmission by aphids causes millions of dollars of damage in the flower bulb sector annually. Mineral oils and pyrethroids are applied weekly during the growth season to decrease the virus transmission in flower bulbs, and current research projects are attempting to learn about the risk of non-persistent virus transmission in relation to aphid population dynamics.
Most recently, population dynamics of aphids in tulip fields were monitored during three growing seasons. Simultaneously, the period of TBV transmission by aphids was investigated experimentally by exposing small tulip plots during specified intervals to naturally occurring aphids. Finally, timing of virus spread was correlated with aphid population dynamics and weather conditions. In 2007 it was discovered that TBV transmission started in April, while the first aphids were not found until May. Apparently, the first aphids of the season had already contributed, in great extent, to the virus transmission, which was observed locally in the tulip plots. In addition, a second, but distinct, TBV isolate was identified, which resulted in the design of an improved TBV detection assay. These results should enable formulatation of crop protection guidelines that are fine-tuned with the risk of virus transmission, which will help decrease environmental damage caused by pesticides.
In an effort to restrict the virus, the United States, Great Britain and other countries prohibit the commercial sale of broken bulbs, or bulbs known to be infected by the virus. As TBV-infected bulbs gradually degenerate, the virus can be minimized by removing and destroying ‘broken’ bulbs quickly before aphids spread the virus to other bulbs or cross-contaminating lilly hosts.
Read more about this topic: Tulip Breaking Virus
Famous quotes containing the word distribution:
“My topic for Army reunions ... this summer: How to prepare for war in time of peace. Not by fortifications, by navies, or by standing armies. But by policies which will add to the happiness and the comfort of all our people and which will tend to the distribution of intelligence [and] wealth equally among all. Our strength is a contented and intelligent community.”
—Rutherford Birchard Hayes (1822–1893)
“The man who pretends that the distribution of income in this country reflects the distribution of ability or character is an ignoramus. The man who says that it could by any possible political device be made to do so is an unpractical visionary. But the man who says that it ought to do so is something worse than an ignoramous and more disastrous than a visionary: he is, in the profoundest Scriptural sense of the word, a fool.”
—George Bernard Shaw (1856–1950)
“There is the illusion of time, which is very deep; who has disposed of it? Mor come to the conviction that what seems the succession of thought is only the distribution of wholes into causal series.”
—Ralph Waldo Emerson (1803–1882)