January 2019 - 14

Minimizing virus spread in seed potatoes
PERCENTAGE OF SEED POTATOES
WITH VIRUS
Kasia Duellman and Erik Wenninger
University of Idaho
Potato virus Y (PVY) continues to
challenge the seed potato industry
across the country, where incidence has
remained somewhat steady for a decade
or more. To combat this now seemingly
chronic challenge, seed potato growers
are willing to adopt unique management
plans into their operations, sometimes
without knowing whether a particular
practice is effective or economical -
in an effort to stave off the risk of
increasing PVY in their potato seed crop
so they can provide a quality product to
their customers.
How PVY moves from infected to
Idaho research is showing that the use of mineral oil with insecticides to help limit
in-season movement of PVY in seed potatoes has not yet been effective. More tests
are planned. Graphic: University of Idaho
healthy plants (the vector): PVY is a
virus that is transmitted to potato by
many species of aphids (vectors) as they
feed on or probe potato plants. The
aphid species most important to moving
PVY are not those that colonize potato,
but rather winged aphids that are leaving
their preferred hosts, such as grain crops,
soybeans, alfalfa or weeds, either due
to aphid crowding or diminishing plant
quality. These transient visitors to potato
can transmit virus to healthy plants
in a matter of seconds - long before
insecticides can kill them.
How PVY survives (PVY reservoirs):
The virus can survive from season to
season in volunteer potatoes and cull
piles - common reservoirs of the virus.
A 2018 survey of volunteers and cull
piles in Idaho showed 5 to 76 percent
incidence of PVY in commercial areas
and 0 to 1.1 percent incidence in seed
growing areas.
Managing in-season
movement of PVY in seed
potato production
For virtually any disease, host plant
resistance is the most sustainable
approach to management. However, most
potato varieties are susceptible to PVY to
some degree. Therefore, managing PVY
focuses on reducing the initial inoculum
and targeting the vectors. No single
tactic by itself will eliminate movement
of PVY from infected to healthy plants.
A multi-faceted approach is usually
adopted, incorporating several of the
following strategies:
* Growing in areas where the PVY
reservoir and aphid pressure are
low (isolation from commercial
fields and from volunteers and
cull piles).
Activate
natural
defenses
now.
Keep your crops primed and
ready to resist disease.
LifeGard®
is the world's first biological
plant activator. Use it to trigger your
crop's built-in immune defenses against
bacterial, viral and fungal diseases.
When crops are primed with an
application of LifeGard, they " switch
on " resistance genes causing a
cascade of metabolic responses that
limit infection and disease
development. LifeGard's activation of
a crop's immune response is known
as induced resistance (IR).
LifeGard is ideal for resistance
management programs for conventional
or organic crops. It's the only fungicide
in the FRAC P6 category, has 4-hour
REI, zero PHI and is residue exempt.
Activate your crops to resist disease.
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800-250-5024 * www.CertisUSA.com
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January 2019

Table of Contents for the Digital Edition of January 2019
