February 2023 - 24

PLANT HEALTH
Scouting Is KEY
Growing outdoors comes with
its ups and downs as the seasons
change, but greenhouse growing is
a year-round operation. This means
controlling pests and diseases is
also a year-round job and requires a
lot of scouting. Continually scouting
the crops you're growing at various
stages - whether that be when
you're taking cuttings or when it's
in a vegetative state or moving
into flower - is the best way to
ensure you are at the forefront of
a problem, says Jeremy Wagnitz,
garden to greenhouse technical
manager for Certis Biologicals.
When growers know what they
should be looking for and what
pathogens the plants are a host
for, they can catch the problem
quickly and begin implementing
control measures right away.
When scouting, knowing symptoms
that specific pathogens cause can
help growers quickly get an idea of
what they are up against, Wagnitz
says. For example, if a root rot
problem is spotted, understanding
that the pathogen Fusarium causes
half of the plant to yellow (symptom)
because it moves through the
vascular tissue can help. A quick
look at the roots could then show
mycelium growth (sign), giving
the grower more information to
properly diagnose the problem.
When a potential disease issue is
found, send in a sample to your local
university diagnostic lab to get proper
identification. Knowing what pathogen
you are battling will make a difference
in the success of your treatment. A
fungicide that works well on powdery
mildew will not work on downy
mildew or Pythium, Wagnitz says.
Resources are imperative to
success. Plant diagnostic labs and
Extension programs are a great
place for information on pests
and diseases. Various university
professors and Extension agents
have developed in-depth guides for
many crop issues, so visiting your
local university can provide the best
knowledge for your specific growing
area. If you want to dive even deeper
into pests and diseases, the American
Phytopathological Society produces
problem. Some of us also run field trials of products
to ensure the products that are labeled for use at your
site type are also efficacious. Labeled for use does not
guarantee that it works very well.
Your Extension specialist has access to science and
data where the products have been field tested under local
growing conditions, to be sure that if there is a product
that will work, we know how well it will work and how
best to apply it, within the legal restrictions and practical
constraints like budget, application technology, and supply.
CALLING FOR BACKUP
This can be a lot to sift through, so you should know
about some of the folks who have your back: The
National Plant Diagnostic Network is a consortium of all
the university diagnostic labs across the country. Built
within the U.S. university Extension system, we provide
unbiased diagnosis and research-based pest management
24
FEBRUARY 2023 GPNMAG.COM
BY HEATHER MACHOVINA
guides, called compendiums, for
most crops that get very specific
about the actual diseases.
Scouting on a regular basis is
crucial in preventing a larger problem
in your production. Pinpointing a
plant that is showing disease right
away and removing it from the
greenhouse will prevent it from
continuing to be an inoculum source
for the rest of the plants, Wagnitz
says. Get the problem plants out and
start using preventative measures
quickly to reduce the spread of
disease. Continue scouting the
area heavily and removing any
other disease sources over the
coming weeks. It's still possible to
get the issue under control even
if the pathogen has spread.
Know the plants you're growing,
what the potential diseases are and
when they are likely to show up
during the growth cycle. Know what
a healthy plant looks like so spotting
abnormalities out of hundreds of
similar plants becomes easier. And
then, know the difference between
biotic versus abiotic stressors.
information. Clicking on your state at www.NPDN.org will
take you straight to your local experts.
Accurate identification of the problem is of prime
importance in effective and cost-efficient plant problem
management. Most of these lab folks work closely with
their crop-specific Extension specialists, keeping the
experts informed about what is popping up in their crop of
interest, and passing along research-based management
information to the grower. This two-way street ensures
we all keep headed in the same direction: healthy crops,
humans and bottom lines.
Carrie Harmon, Ph.D., has worked in diagnostics for 20 years
and currently leads a research, teaching, and Extension program
that focuses on disease diagnosis, assay development, and
diagnostic training at UF-IFAS Plant Diagnostic Center and
National Plant Diagnostic Network in Gainesville, Florida.
She can be reached at clharmon@ufl.edu.
http://www.NPDN.org http://www.GPNMAG.COM
February 2023

Table of Contents for the Digital Edition of February 2023
