December 2019 - 8

INDUSTRY NEWS
from americanhort to you
New Rose Rosette Detection Under Way
BY DR. JILL CALABRO,
RESEARCH & SCIENCE DIRECTOR
AMERICANHORT & HORTICULTURAL
RESEARCH INSTITUTE
One of the most important tenets of plant
pathology is that the first step to effectively
controlling a plant disease is identifying its
cause. Otherwise, control measures could be
ineffective, leading to further plant loss and
wasted time and resources. This is especially
true of rose rosette disease (RRD).
Typical symptoms of RRD are known and
widely accepted; they include rapid elongation
of new shoots, witches' brooms, small or
distorted leaves, red pigmentation of stems
or foliage, and excessive thorn development.
However, none of these symptoms is
guaranteed to be expressed when the disease
is present, especially early in the disease cycle.
An infected rose may have something as subtle
as a thickened cane or flowers with fewer
than normal petals - either of which could be
easily overlooked or dismissed as a nutrient
deficiency or even herbicide injury. Early RRD
symptoms can be diverse in expression and
may vary based on age of plant, cultivar and
environmental conditions, but later in the
disease cycle, symptoms usually become overt
and obvious. But by this stage, RRD has likely
spread to neighboring plants.
The simple fact that RRD is caused by a
virus alone, makes confirmation of the disease
more challenging. There are no obvious signs
of the disease's presence like with powdery
mildew where white, powdery spores are
prominent on leaf undersides. Complicating
matters further, infected plants can be
symptom-free for months, and viruses cannot
be seen with a microscope, let alone a naked
eye. Eriophyid mites transmit the virus, but
even the mites are difficult to find. They are
too small to be seen with the naked eye and
are often difficult to find. Diagnosticians and
scouts have no choice but to rely on visible,
observed symptoms, until serological and/
or molecular techniques can be conducted in
the lab.
Nebulous expression of symptoms early in
the disease cycle is exactly why researchers
direct their energies toward diagnostic tools
development. In the case of RRD, it is critical
to find a means of quick and easy diagnosis,
preferably without having to destroy the plant.
Researchers have been working since 2014 on
various aspects of RRD through a multi-year,
multimillion dollar grant titled 'Combatting
Rose Rosette Disease' funded by USDA NIFA,
and development of diagnostics has been a
key component. Knowing sooner that a plant
is infected will, in the very least, help limit
spread and movement of the disease.
A small team of researchers, part of the
larger group mentioned above, from Texas
A&M, led by Dr. Dmitry Kurouski, developed
a new diagnostic tool for RRD detection.
Using a hand-held, portable spectrometer,
Dr. Kurouski's team has correctly identified
the virus in leaves both non-invasively and
non-destructively, with an almost instant
read. Raman spectroscopy works by relying
on light to interact with molecular vibrations
in a leaf. A 'fingerprint' is made based on
these vibrations, meaning that the virus
that causes RRD is identified by its unique
fingerprint. Previously the team proved that
this technology could identify fungal diseases
on corn, wheat, and sorghum and eventually
adapted it to successfully compare healthy
and asymptomatic rose leaves, as well as
symptomatic and asymptomatic leaves. They
could even differentiate rose leaves with
different degrees of infection.
While not yet ready for widespread adoption
and use in the industry, this tool can help
diagnostic labs by acting as an initial screen
for RRD that can help save on more costly,
molecular techniques. Plus it may be available
for use in the field one day!
The American Rose Society provided small
research grants for a portion of this work.
AmericanHort and our Horticultural
Research Institute affiliate, in conjunction
with likeminded organizations such as the
Society of American Florists, previously
supported funding of rose rosette research at
the University of Arkansas through the Farm
Bill Section 10007. AmericanHort participates
on the advisory board of the Specialty Crop
Research Initiative (SCRI)-funded Combatting
Rose Rosette Disease project.
For more information, visit americanhort.org
or hriresearch.org.
NEW ORGANIC
PUBLICATION TO
LAUNCH
Great American Media
Services, the parent
company of GPN, Lawn & Garden Retailer, Fruit Growers News, Vegetable
Growers News, Spudman and Produce Processing, has announced the
launch of Organic Grower.
The new print and digital brand will focus on the unique needs of the
organic farming community, offering in-depth coverage of the latest news
and products to keep the industry informed and ahead of trends.
The Organic Grower brand will be a fully integrated multimedia brand
with a vibrant social media presence, weekly e-newsletter, website
8 DECEMBER 2019 GPNMAG.COM
and quarterly print magazine. The content will be created by a team
of seasoned journalists and thought leaders with expertise on organic
growers, researchers, crop consultants, processors, packer/shippers and
related associations. Each print issue will focus on the most pertinent
issues facing the organic growing industry, including planting systems,
pollinators, weed control, disease control, pest control, food safety,
organic certification/audits, labor, soil health, crop rotation and more.
The need for Organic Grower was determined after extensive surveying
of the industry, which revealed challenges currently faced by organic
growers and a lack of informative resources specific to their needs.
In addition, the research demonstrated significant growth of organic
growing, with 61% of respondents indicating they intend to expand their
organic production in the coming years.
http://www.americanhort.org http://www.hriresearch.org http://www.GPNMAG.COM
December 2019

Table of Contents for the Digital Edition of December 2019
