A comprehensive national effort among 30 industry and academic entities led by Texas A&M is gaining ground in the battle against rose rosette.
The disease has claimed an estimated $40-$50 million in rose industry losses alongside thousands of jobs, researchers said.
The team has tracked the disease across the U.S., developed new diagnostic tools and expedited breeding with hundreds of new molecular markers.
Tracking Rose Rosette
Since the project’s beginning in 2014, part of its $4.6 million grant helped establish https://roserosette.org. The website serves to track disease distribution, said Dr. Kevin Ong, director of Texas A&M AgriLife Extension Service’s Texas Plant Disease Diagnostic Lab in College Station. It is also a clearinghouse for educational rosette information.
Pathologists have verified more than 2,100 rose rosette occurrences in about 30 states through user photo submissions to the website so far.
Detecting the disease
Researchers continue to test an array of genomic tools they’ve developed since 2014 to verify reported rose rosette. The group’s plan – along with renewal of their U.S. Department of Agriculture grant in 2020 – is to produce a serological test, which functions like a home pregnancy test for rose rosette in the field.
Understanding the virus
The initiative’s virology team, led by Dr. Jeanmarie Verchot with Texas A&M AgriLife Research in Dallas, seeks solutions to rose rosette from clues about its underlying emaravirus. The team seeks to capture the virus in field plots at Dallas, and to clone it for observation under greenhouse conditions.
Controlling the mite
In another aspect of the rosette initiative, entomologists seek to control populations of the eriophyid mite Phyllocoptes fructiphilus. The arachnid is currently known as the sole distributor of the virus among roses, and entomologists are seeking vector-control methods beyond excessive, expensive miticide application.
Still, he said, any mite control measures will need to be bolstered by naturally resistant plants.
Breeding resistant roses
About 4% of roughly 1,200 rose cultivars observed during the ongoing grant period exhibit resistance potential after three years, Byrne said.
About 3,000 markers are now identified, compared to roughly 150 at the grant’s beginning. The new markers are unassociated with rose rosette. But based on other traits they represent, they allow researchers to weed out 50% to 75% of seedlings as poor candidates early in horticultural greenhouse trials.
With a 2020 grant renewal, teams will screen commercial roses for resistance, guaranteeing solutions are more applicable to desirable industry varieties, Byrne said.
His team plans to implement field spectral imaging to detect pre-symptom responses to rose rosette. They also seek better screening techniques off the field; insights into environmental characteristics of the vector eriophyid mite; and bolstered reporting of rose rosette to the national website.
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