Agriculture Reference
In-Depth Information
blight, and skin conditions such as scab, silver
scurf,
Rhizoctonia
damage, and bruising. Each
of these must meet the appropriate tolerances
for the class being shipped. It is also during this
time that phytosanitary aspects are considered.
Depending on where the seed is destined,
either in-country or as an international export,
the phytosanitary restrictions for each location
receiving seed must be met and officially docu-
mented by a government agent. Meeting region-
specific phytosanitary conditions assures the
buyers they will not be receiving unwanted or
non-endemic diseases or pests in the seed pota-
toes. Seed potatoes can be an effective mechan-
ism for transporting diseases and pests between
regions. Therefore, it is critical that only seed
meeting the specific phytosanitary restrictions
of each region be moved.
The final step of the certification process is
tagging the seed lot with an official certification
document. Documentation includes a substan-
tial amount of information describing the seed
lot's identity, and assists in tracing the seed lot
for re-certification eligibility.
Information on the tags (for individual
sacks or smaller containers) or bulk certificates
includes: the term “certified seed potatoes”; the
country or state of origin; the seed grower's name
and address; the cultivar; the unique lot identifi-
cation; year of production; date of certification;
grade of the potatoes (often designated by the color
of the tag); the class (often designated by the color
of the tag); net weight; and other pertinent infor-
mation such as size or phytosanitary specifics.
Usually, a seal with a unique identifying number
for each load is attached to the conveyance (truck,
bin, rail car, container, etc.) after shipping point
inspection to prevent unwarranted additional
inspections or tampering of the seed (NIVAP,
2005; SASA, 2013; Sather
et al
., 2013). The seal
is to be removed by the buyer or recipient of the
seed, and together with the official paperwork,
constitutes the final act in the certification pro-
cess. Buyers of certified seed recognize these
steps and expect each certification program will
honor their commitment to this process.
(Secor
et al
., 1985). Sanitation at every stage of
production is not only essential but also keeps
pathogens and pests from moving into the oper-
ation. If the field soil is contaminated with a
pest, sanitation will not help the potatoes within
that field, but can help keep the pest from mov-
ing from one field to the next. Each phase of a
seed operation should have sanitation steps, but
they are particularly important in phases where
the tubers come into contact with other tubers
and/or machinery, such as in sorting, cutting,
planting, harvesting, and loading.
In general, pathogens and pests move from
one tuber to the other when an infected tuber
comes into contact with either equipment or
other tubers. A prime example is the spreading
of soft rot through active bacteria on a rotting
potato, and subsequent tuber-to-tuber contact
during movement operations, which transfers
the bacteria between tubers. If conditions are
right, then the previously non-infested tuber can
become infected and start to decompose (Bohl
and Johnson, 2010).
Proper sanitation starts with the cleaning
of equipment, storage units, floors, and building
surfaces with steam to remove the adhering soil,
and is followed with the proper application of an
effective disinfectant. Disinfectants must be ap-
plied to all surfaces at the appropriate concen-
tration and left for the recommended exposure
time (usually
5-10
min). There are many disin-
fectants available, so it behooves the producer to
understand the effectiveness of each disinfectant
(e.g. which pathogens it controls), whether or
not it is deactivated by organic matter, hard water,
or is corrosive to metal, and the safety information.
When used properly on equipment and storage
surfaces, effective sanitation can go a long way
toward stopping the spread of several serious
pathogens on seed potatoes, including bacteria,
viruses, fungi, and certain pests.
8.6 Early-Generation Stocks:
Types and Production Systems
The starting point for global certification pro-
grams is the use of tissue culture
in vitro
stocks.
The stocks are tested for pathogens or line selec-
tions that have been isolated and tested for
pathogens themselves. In developed regions,
most certification programs use tissue culture
8.5 Sanitation
Sanitation is one of the single, most critical com-
ponents of any seed potato production operation
