Spudman April 2023 - 8

The PAPAS project
Integrated nematode management in potatoes
By Nancy Power
CONTRIBUTING EDITOR
A
bout 20% of what a farmer
spends to grow a crop of potatoes
is for nematicide applications.
In Idaho, the pale cyst nematode
(Globodera pallida) alone causes a loss
of $25 million per year, even though it
occurs on only 1% of the potato acreage
in the state. If left unmanaged, such
potato cyst nematodes (PCN) can cause
upwards of 80% yield loss.
Under strict regulations by USDA -
APHIS (Animal and Plant Health
Inspection Service), so far, the pale cyst
nematode occurs only in Idaho. Root
knot and lesion nematodes, though, are
widespread. In some cases, if only 6% of
a shipment has signs of the Columbia
root knot nematode (RKN), the whole
shipment is destroyed.
To lessen the costs and increase the
effectiveness of nematode control,
a group of 17 scientists are working
to improve science-based nematode
management strategies. Led by LouiseMarie
Dandurand of the University
of Idaho, the research effort is called
Potatoes and Pests: Actionable Science
Against Nematodes (PAPAS). The
project is supported by a $6.8 million
dollar grant from the U.S. Department
of Agriculture-National Institute of
Food and Agriculture.
As the PAPAS website notes: " Plantparasitic
nematodes pose a continuous
threat to potato production in the
U.S., and the viability of international
markets for U.S. potatoes. "
Potato nematodes reduce yield and
cause internal and external defects,
lower the potato market value and
cause crop rejection.
The PAPAS research will expand the
foundation for Integrated Nematode
8
Spudman * April 2023
Tuber infected with root-knot nematodes. Photo: Cynthia Gleason, lab at Washington
State University.
campaign to develop decision support
models, nematode-resistant potato
varieties and new nematicides.
The first initiative is to improve the
A broken-open cyst of a potato cyst
nematode, showing the hundreds of
nematode eggs in just one cyst. A cyst
can survive for 20+ years in the soil in the
absence of a host crop. Photo: Dandurand
program at University of Idaho.
Management for nematode management
in potato. Hailing from the USDA
Agricultural Research Service and
universities in Washington, Oregon,
New York, Michigan and Idaho, the
researchers employ a three-pronged
molecular diagnosis of nematode races
and species, along with better estimates
of nematode incidence and population.
The scientists will use the nematode
identification and the population data
to create action thresholds and decision
models that enable growers to better
predict the nematode damage facing
their farm so they can choose strategic
actions and use less of the expensive,
toxic nematicides.
The second prong of the research
is to develop commercial potato
varieties that can resist both PCNs and
RKNs. Already resistant varieties are
available for the golden (cyst) nematode,
Globodera rostochiensis, found only in
New York, but not for G. pallida, found
only in Idaho. A third cyst nematode,
G. ellingtonae, found in Oregon and
Idaho, was described as a new species
in 2012. Because cysts with viable eggs
can last in the soil for decades, the cyst
Spudman April 2023

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