Cautiously optimistic: Study looks for riskiest tree disease spreaders,
finds none
This study is believed to be the largest pre-invasion risk assessment of exotic tree pathogens ever conducted.

Date:
February 9, 2022
Source:
University of Florida
Summary:
Fungal disease represents one of the greatest threats to tree
industries and forests in the United States. They're carried by
invasive wood borers from overseas. A pre-invasion risk assessment
tested 111 fungi samples extracted from 55 Eurasian beetles. None
of the greenhouse-grown oak or pine saplings inoculated with the
fungi died during the study period, and only a few fungi were
shown to be weak pathogens.



FULL STORY ========================================================================== Scientists seek answers through research, but sometimes, a lack of
findings can be good news. A recent University of Florida-led study
involving tree diseases uncovered no remarkable threats to common
Southeastern United States trees, and the lead researcher says to file
it as a cautiously optimistic "win."

========================================================================== Think of the 27-expert, nine-country survey team as tree epidemiologists, looking for the next "tree pandemic" that could decimate North American forests. Just one beetle could spread the next laurel wilt disease
-- a fungal infection carried by ambrosia beetles that's currently
troubling South Florida's avocado industry -- and as with human diseases, researchers know an ounce of prevention is worth a pound of cure.

It was a positive sign, then, that none of the greenhouse-grown oaks
and pines in the study died or revealed other ill effects after being
exposed to fungi from foreign wood-boring beetles, said Jiri Hulcr, lead researcher on the study and associate professor of forest entomology in
the UF/IFAS School of Forest, Fisheries, and Geomatics Sciences. One of
the greatest threats to tree industries and forests in the United States
is fungal diseases carried by invasive wood borers from overseas.

"It's certainly worthwhile," Hulcr said of the pre-invasion risk
assessment the team undertook. "If we had used the same method on
laurels or elms years ago, we would have detected the laurel wilt and
Dutch elm disease fungi ahead of time. This is one of the moments when
a negative result is great news. A proactive exploration of dangers
is more effective than a 'sit and wait' strategy." Aiming to identify
which foreign beetle species posed risks if introduced to North American forests, the UF/IFAS Forest Entomology Lab connected with scientists
worldwide to collect 55 species of Eurasian wood-boring beetles,
from which they extracted 111 fungi samples. These fungi samples were
brought to greenhouses managed by a collaborating agency on the study,
the Florida Department of Agriculture and Consumer Services Division of
Plant Industry (FDACS-DPI), in Gainesville.

There, the fungi were introduced, in a highly controlled environment,
to 4- year-old saplings of species common to the Southeastern United
States. At the conclusion of the 10-week study, all trees were still
alive. Only some trees bore marks of infection, and Hulcr noted the
fungi that caused these signs will be studied further.

"We did detect several beetle-associated fungi that are weak pathogens,
but most exotic fungi appear to be harmless," Hulcr said.

Nearly half of the land area in Florida -- some 25,000 acres --
is forested.

Hulcr said it was important to look at Southeastern tree species in the
pre- invasive risk assessment because this region's dense forest cover
can often aid in the spread of invasive species.

"Mostly, this study shows the effectiveness and value of risk
assessments," Hulcr said, explaining that the team believes this study
to be the largest pre- invasion assessment of exotic tree pathogens
conducted worldwide. "We only scratched the surface with the potential pathogens that exist out there; but we have shown that risk assessment
for these diseases is not just possible, but effective." The research
was supported by the United States Department of Agriculture's Animal
and Plant Health Inspection Service (USDA-APHIS), USDA Forest Service, FDACS-DPI, and the UF Emerging Pathogens Institute.

========================================================================== Story Source: Materials provided by University_of_Florida. Original
written by Kirsten Romaguera. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. You Li, Craig Bateman, James Skelton, Bo Wang, Adam Black,
Yin-Tse Huang,
Allan Gonzalez, Michelle A. Jusino, Zachary J. Nolen, Stanley
Freeman, Zvi Mendel, Miroslav Kolaři'k, Milos Kni'žek,
Ji-Hyun Park, Wisut Sittichaya, Thai-Hong Pham, Shin-ichiro Ito,
Masato Torii, Lei Gao, Andrew J. Johnson, Min Lu, Jianghua Sun,
Zhen Zhang, Damian C. Adams, Jiri Hulcr. Preinvasion Assessment
of Exotic Bark Beetle-Vectored Fungi to Detect Tree-Killing
Pathogens. Phytopathology(R), 2022; DOI: 10.1094/ PHYTO-01-21-0041-R ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220209154805.htm

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