July/August 2005
Predicting,
Manipulating and
Managing Tuber Yield Potential
The day is coming when seed potato growers will be able to customize
their seed lots according to the areas where they will be grown. Each
lot will be physiologically aged to produce the exact number of stems
scientifically proven to produce an optimal marketable yield. Those
numbers will be different for longer-season areas such as the Columbia
Basin versus areas where the season is shorter.
Sound like pie in the sky?
Not according to Dr. Rick Knowles, Professor, Postharvest Physiology & Biochemistry
Lab, Department of Horticulture, Washington State University, Pullman. His research
shows that seed can be manipulated to come up with a whole range of stem numbers,
and among those the ideal stem number for producing an optimal crop in a particular
area can be identified.
“Right now, most growers pay little attention to stem numbers,” Knowles
points out. “They select a seed grower, purchase their seed and then plant
whatever they get. The larger operators monitor physiological age of their seed
about like they do their planter settings. They may pay attention during the
first trip down the field but then forget to re-check and see if anything has
gotten out of whack. Their operations may be so big that they feel any economic
loss will be hidden. Likewise, the economic importance of planting seed with
the correct stem number is poorly understood.”
Management
Strategies for
Tuberworms in Potatoes
Why should potato growers be concerned about possible tuber worm damage in
the Pacific Northwest, and can they afford to ignore having a management strategy
in place?
Both questions took center stage during a May 26 teleconference discussion, “Management
Strategies for Tuberworms in Potatoes,” sponsored by DuPont.
Participating on the panel were: Mel Martin, manager of raw product development,
J. R. Simplot Co., Moses Lake, Wash.; Dr. Andy Jensen, director of research,
Washington State Potato Commission; Phil Hamm, an extension plant pathologist
at Oregon State University; Dale DeShane, president of Supervise Control Service
Inc., Bakersfield, Calif..; and Dan Sherrod, product development manager, DuPont
Technical Development, Memphis, Tenn.
Martin warned the listening audience of growers, field men and others involved
in potato production that the economic risks are just too great to take the threat
of a possible tuber moth infestation lightly.
Preparedness: An Educated Approach to “Perfect
Potatoes”
“Four eyes” is a derogatory term in most
situations. But not when it applies to scouting for potato insect problems
in the Columbia
Basin, says Todd Hines, an independent crop consultant and owner of Cascade
Agronomics, Moses Lake, Wash.
The more eyes the better, especially this year, he says. Hines notes
that the arrival of fairly new pests, such as the tuberworm and leafhopper,
coupled with the presence of more traditional pest problems, such as
the Colorado potato beetle, have generated a high level of concern among
producers and fieldmen alike.
“
It’s pretty scary out here right now,” says Hines, who works
with producers in eastern Washington.
And he’s not the only one who fears an onslaught of pests this
season.
Some processors have adopted a zero tolerance level for worm presence
in tubers, notes Denis Miller, DuPont district sales manager. “Processors
cannot afford to have a worm show up in their products at the consumer
level,” he says, adding that many processors have only a five percent
tolerance level for tuberworm damage. He and other DuPont field staff
are working closely with Washington potato producers to generate greater
awareness for this critical pest problem, which many growers have not
encountered before now.
“One live worm in a sample could result in the entire lot being rejected,” Miller
says.
Potato Quality
Improvements Shown in
Oregon-Washington AuxiGro Study
By Dr. Terry A. Tindall
Senior Agronomist, J.R. Simplot Co.
Growing conditions in the Columbia Basin of Washington
and Oregon seem to contain some of the most ideal conditions in North
America to produce
high-yield potatoes for processing. The processing contracts demands
for higher quality tubers continue to push growers to finely tune management
decisions. A grower’s decision to include inputs and products that
were not available a few years ago may make a positive difference on
both his yield and quality. Some of these emerging materials fall into
the category of “soft chemistry,” such as AuxiGro, and may
have a beneficial place on grower’s fields.
Nutritional requirements of N, P, K and other nutrients for a potato
are high. This is especially true in the Columbia Basin where yields
are approaching 50 tons (1000 cwt). As a plant grows and develops within
these conditions, it is continually balancing internal requirements to
sustain smooth tuber growth and to avoid abrupt changes that disrupt
this growth. These are simple to state but difficult to obtain because
of the challenges potato growers have in any area producing large yields
with high processing quality.
HAREC Research Important to Columbia
Basin Potato Industry
With current concerns about tuber moth in the Columbia Basin, potato
research at the Hermiston Agricultural Research and Extension Center
(HAREC) in Hermiston, Ore., has taken on an even more important role.
Tuber moth research is No. 1 in terms of acreage committed to a particular project,
according to Phil Hamm, Extension plant pathologist and the new station superintendent.
Approximately five acres have been committed to various tuber moth studies underway.
The station is particularly valuable because the pest was first identified in
the Pacific Northwest in the Hermiston area, Hamm, says. The number of moths
being caught in pheromone traps is larger than anywhere else in the Columbia
Basin. Whether that is due to warmer weather patterns in the southern part of
the Columbia Basin or for other reasons, no one knows. However, what’s
happening with the insect in the Hermiston area is being closely watched by the
coalition of researchers from both sides of the Columbia River in pooling their
expertise.
“Our tuber moth numbers here remain higher than in other parts of the Basin,
but we know that the numbers north of us are higher than they were a year ago,” Hamm
says. “This likely means the moths first established themselves here and
are now spreading northward and taking up residence. With the tuber moth count
expected to be higher at the end of the season than a year earlier, the risk
of tuber damage this fall is likely higher over a larger area.”
Economic Impact Study Assesses Loss of Potato Farming
Washington State University (WSU) researchers have taken a look at what could
happen if potato farms in the water-challenged Odessa aquifer region dried up
and went away.
In 2005 the Washington State Potato Commission (WSPC) retained Dr. David Holland
and Sanjoy Bhattacharjee of the School of Economic Sciences at WSU to measure
the regional economic impact of a possible loss of potato production and subsequent
potato processing due to a loss of irrigation water in an area known as the Odessa
Sub-Basin.
The Odessa Sub-Basin is located in parts of Lincoln, Grant, Adams and Franklin
counties, which include 35,611 acres of irrigated potato land that have been
developed with private funds, using deep wells and pumping from the underlying
aquifer.
The study measured the potential economic impact to the region if the area were
to lose all, or part, of the irrigated potatoes and subsequent frozen potato
processing. It also measured the economic impact to the area if these acres are
converted back to summer fallow dry land wheat production.
The difference between growing irrigated potatoes and processing them into frozen
potato products compared to dry land wheat production is enormous. An acre of
irrigated potatoes and subsequent potato processing generates $17,700 of regional
economic activity each year, of which $5,045 is attributed to growing the acre
of potatoes and $12,655 per acre to processing. The total regional economic impact
from an acre of dry land wheat in comparison is only $113.