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What is the method of Transport - the Disease Vector?                                         

A wind blown microscopic wingless mite, 'Phyllocoptes fructiphilus' is credited with the spread of the disease in nature. This is  NOT A SPIDER MITE, but  is one of  about 3,100 known species of
eriophyoide mites some of which spread plant viruses. P. fructiphilus has been shown to transmit RRD
from plant to plant, and is the predominant agent of transmission in nature. The mite was first described
by Hartford H. Keifer in 1940 from a sample collected at Clarksburg, CA on December 15, 1939 on a healthy R. californica and described in the Bulletin of the Dept of Agriculture of the State of California
Vol. XXIX Number 1 Jan/Feb. 1940 (see line drawing of the ugly bug below). The total length of this bug is 140 to 170 microns-esentially invisible without a hand lens, barely visible with a 20x hand lens.
Another, potentially more insidious  method of transport would be the sale, trade or barter of RRD
infected roses. If  RRD were to enter commercial rose fields unnoticed, the disease could spread rapidly.  See Chapter 10 for more information.  When a RRD-diseased rose enters a rose garden (from whatever source), the mites are the agent of spread within the garden.                    
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