Woodlands - Fall 2017 - 6

ON THE GROUND

Seedlings

FOREST-EATING CATERPILLARS MEET THEIR MATCH
Fungal Spore 'Death Clouds' Key in Gypsy Moth Fight

6 WOODLAND * Fall 2017

to create a hole and enter the
caterpillar's body, where a cloaking
mechanism allows the fungus to
remain undetected by the moth's
defenses. Over four to six days, the
fungus multiplies and then kills the
host, after which new spores are
literally shot from the cadaver into the
air, where they become windborne.
From May through June, when
gypsy moth caterpillars are feeding
and before they pupate, the fungal
pathogen can run through up to nine
infection cycles, while the numbers
of infections increase dramatically.
During the study, the researchers
found the peak caterpillar death
rate due to E. maimaiga reached 86
percent, meaning that if you found 100
caterpillars munching leaves that day,
86 of them would die within the week.
In the past, researchers studied
the airborne spores by collecting air
samples on a transparent surface and
studying particles under a microscope,
a time-consuming and potentially
inaccurate process, Bittner says.
The new method makes use
of quantitative polymerase chain
reaction (PCR), a standard method
for quantifying RNA and DNA. The
researchers designed a trap, a
chamber with a hole on the top.
"Whatever is falling in the air can
fall into that hole," Bittner says. A cup
in the bottom of the trap contains a
buffer that prevents the spores from
germinating but preserves each
spore's DNA.
Back in the lab, the researchers
filtered the contents of each trap for
pollen-sized particles, then measured
the amount of E. maimaiga DNA

in each sample using quantitative
PCR. "We found there was a
correlation where if the trap was
closer to a defoliated area, it had
more spores, and further away it
had fewer spores," Bittner says. "We
did detect spores in a trap that was
70 kilometers [43.5 miles] from a
defoliated area."
A
Source: Cornell University

Joan DG/Shutterstock

A fungus known to decimate
populations of gypsy moths creates
"death clouds" of spores that can travel
more than 40 miles to potentially infect
populations of invasive moths, according
to a new Cornell University study.
That's good news as gypsy moth
(Lymantria dispar) caterpillars ravage
the leaves of forest trees - especially
oak and aspen - decimating forests,
orchards and properties across the
northeastern United States. In 2016,
gypsy moth caterpillars ate the leaves
off 350,000 acres of forest plants in
Massachusetts alone.
The study, published in the journal
Applied and Environmental Microbiology,
describes a new method for tracking
the geographic range of this airborne
insect pathogenic fungus from areas of
a disease outbreak.
Better understanding of the
distances these killer spores travel
could help researchers correlate the
fungus' range with weather patterns
to better predict how bad gypsy moth
damage will be in a given year.
"One spore can infect a gypsy moth
caterpillar and kill the insect, and after
it's dead, the fungus can use the body
to make one million more spores. An
insect is a huge source of nutrients
for making spores," says Ann Hajek,
professor of entomology and a coauthor of the paper. Tonya Bittner, a
postdoctoral associate in Hajek's lab,
is the paper's first author.
The fungal pathogen (Entomophaga
maimaiga) first appeared in New
England in 1989 and only infects gypsy
moths. The pollen-sized spores stick to
caterpillars when they walk over them.
Once attached, a spore uses enzymes



Table of Contents for the Digital Edition of Woodlands - Fall 2017

Overstory
Tools and Resources
Forests and Families
A Legacy to Keep
From Forests to Fermentation
Feathering a Forested Nest
Woodlands - Fall 2017 - intro
Woodlands - Fall 2017 - cover1
Woodlands - Fall 2017 - cover2
Woodlands - Fall 2017 - 3
Woodlands - Fall 2017 - Overstory
Woodlands - Fall 2017 - 5
Woodlands - Fall 2017 - 6
Woodlands - Fall 2017 - 7
Woodlands - Fall 2017 - 8
Woodlands - Fall 2017 - 9
Woodlands - Fall 2017 - 10
Woodlands - Fall 2017 - 11
Woodlands - Fall 2017 - 12
Woodlands - Fall 2017 - 13
Woodlands - Fall 2017 - 14
Woodlands - Fall 2017 - 15
Woodlands - Fall 2017 - 16
Woodlands - Fall 2017 - 17
Woodlands - Fall 2017 - Tools and Resources
Woodlands - Fall 2017 - 19
Woodlands - Fall 2017 - Forests and Families
Woodlands - Fall 2017 - 21
Woodlands - Fall 2017 - 22
Woodlands - Fall 2017 - 23
Woodlands - Fall 2017 - A Legacy to Keep
Woodlands - Fall 2017 - 25
Woodlands - Fall 2017 - 26
Woodlands - Fall 2017 - 27
Woodlands - Fall 2017 - 28
Woodlands - Fall 2017 - 29
Woodlands - Fall 2017 - From Forests to Fermentation
Woodlands - Fall 2017 - 31
Woodlands - Fall 2017 - 32
Woodlands - Fall 2017 - 33
Woodlands - Fall 2017 - Feathering a Forested Nest
Woodlands - Fall 2017 - 35
Woodlands - Fall 2017 - 36
Woodlands - Fall 2017 - 37
Woodlands - Fall 2017 - 38
Woodlands - Fall 2017 - cover3
Woodlands - Fall 2017 - cover4
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