Phytosanitary Measures for Seeds - nappo
Phytosanitary Measures for Seeds - nappo
Phytosanitary Measures for Seeds - nappo
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<strong>Phytosanitary</strong> <strong>Measures</strong> <strong>for</strong><br />
<strong>Seeds</strong><br />
Field Inspections<br />
Seed Testing<br />
Seed Treatments
Seed Industry Perspective on<br />
<strong>Phytosanitary</strong><br />
• Presence of any pest reduces seed quality<br />
• Seed Companies have designed and<br />
implemented QM programs to reduce<br />
exposure to, and eliminate seed pests<br />
throughout production life cycle<br />
• ASTA Guide to Seed Quality Management<br />
Practices<br />
• Federal Seed Act<br />
• OECD Seed Schemes
Seed Industry Perspective on<br />
<strong>Phytosanitary</strong><br />
• The seed industry employs the same<br />
methods as the NPPOs require to<br />
manage, monitor, and ensure seed quality<br />
• <strong>Phytosanitary</strong> field inspections<br />
• Seed testing <strong>for</strong> pests<br />
• Seed treatments<br />
• Front line method <strong>for</strong> industry:<br />
phytosanitary field inspection
<strong>Phytosanitary</strong> Field<br />
Inspections<br />
• Companies conduct their own<br />
inspections <strong>for</strong> many pests<br />
Monitor pathogen races<br />
e.g: Exserohilum turcicum
Agricultural Industry:<br />
Pests Data Collection<br />
<strong>Phytosanitary</strong> Field Inspections<br />
To document the<br />
absence of a quarantine<br />
pest is just as important<br />
as recording their<br />
presence.<br />
Several ASTA member companies are<br />
accredited <strong>for</strong> <strong>Phytosanitary</strong> Field Inspection<br />
under USDA-APHIS-PPQ-National Seed Health<br />
System
<strong>Phytosanitary</strong> Field Inspections<br />
(NSHS)<br />
• Establish the seed field inspection pattern<br />
• 1. The seed field inspection pattern should<br />
ensure that all parts of the field are adequately<br />
and proportionately represented in the plants<br />
inspected within the various usual microclimates<br />
of the field.<br />
• 2. As long as these requirements are met, the<br />
pattern of field inspection can vary.
<strong>Phytosanitary</strong> Field Inspections<br />
(NSHS)<br />
• Stagger “X” pattern: used <strong>for</strong> cereal<br />
crops<br />
• Equidistant passes pattern: used <strong>for</strong><br />
crops other than cereals<br />
• Design <strong>for</strong> field inspections: determine the<br />
minimum number of field passes in<br />
relation to field size to give a minimum of<br />
95% confidence level in detecting an<br />
infection level of 0.1%.
Table 1. Minimum field passes per acre.<br />
Field size (acres) Minimum # passes<br />
0 - 1 6<br />
1 - 5 9<br />
5 - 10 11<br />
10 - 20 13<br />
20 - 50 17<br />
50 - 100 20<br />
100 - 200 24<br />
200 - 500 30<br />
500 – 1000 36<br />
1000 + 42
Advantages of Field<br />
Inspections<br />
• Allows a large number of plants to be<br />
inspected (one plant can represent<br />
thousands of seeds)<br />
• Plants exhibiting symptoms are tested to<br />
confirm<br />
• Infected plants/fields are removed;<br />
potentially infected seeds don’t enter<br />
channels of trade
Advantages of Field Inspection<br />
• Identification of special areas or microclimates<br />
in the field that appear different<br />
enough to warrant special attention when<br />
inspected. These would include:<br />
• Rivers and streams<br />
• Drainage areas<br />
• Low spots<br />
• Weedy areas
Advantages of Field Inspection<br />
• Areas of the field affected by borders,<br />
such as:<br />
• Field edges<br />
• Tree lines in the field<br />
• Adjacent fields of a similar crop<br />
• Presence of buildings or bins
Advantages of Field Inspection<br />
• Drought stress areas, such as:<br />
• High spots<br />
• Light textured soils<br />
• Margins or overhead irrigation areas
<strong>Phytosanitary</strong> Seed Testing<br />
• Should only be used <strong>for</strong> pests/pathogens<br />
<strong>for</strong> which seed is known to be a pathway<br />
• Often used when a phytosanitary field<br />
inspection was not conducted (some<br />
NPPOs require field inspection plus a<br />
seed test)<br />
• Often used to monitor/verify effectiveness<br />
of an import program
<strong>Phytosanitary</strong> Seed Testing<br />
Issues<br />
• Use of “official” methods: system works<br />
best when NPPOs of both exporting and<br />
importing countries use the same method<br />
• Problems occur when different test<br />
methods are used <strong>for</strong> the same<br />
pest/pathogen<br />
• Problems can occur when regulatory<br />
decisions are based on protein or DNA<br />
based methods
<strong>Phytosanitary</strong> Seed testing<br />
Issues<br />
• Accuracy based on accuracy of the seed sample: is the<br />
sample representative of the seed lot<br />
• Need to use official seed sampling methods; e.g.,<br />
AOSCA<br />
• Accuracy based on sensitivity of method<br />
• Protein and DNA based PCR tests assume correct<br />
primers are used<br />
• Primers often react to other strains or even species of<br />
pest/pathogen, producing false positives
<strong>Phytosanitary</strong> Seed Testing<br />
Issues<br />
• Protein and DNA based methods do not<br />
necessarily mean the pest/pathogen is<br />
viable!<br />
• Biological test methods (blotter tests, agar<br />
assays, etc.) provide the most definitive<br />
results, but can be time consuming<br />
• Viruses: usually show symptoms (field<br />
inspection), but require protein or DNA<br />
based test methods
Seed Treatments<br />
• Many countries accept seed treatments <strong>for</strong><br />
mitigating pests of phytosanitary concern<br />
• Often when field inspections were not<br />
per<strong>for</strong>med <strong>for</strong> the pest of concern (e.g. reexport)<br />
• Sometimes can be per<strong>for</strong>med at port of entry<br />
• Sometimes issues with registrations and<br />
dosages of the active ingredient
Seed Treatments<br />
• Emerging technologies offer promise<br />
• Good opportunities <strong>for</strong> harmonization<br />
among countries<br />
• Issues with organic seed
Summary<br />
• <strong>Phytosanitary</strong> field inspections offer significant<br />
protection against seed pests by preventing<br />
pests from getting into channels of trade<br />
• Seed tests <strong>for</strong> phytosanitary purposes work best<br />
when NPPOs use the same methods<br />
• Both seed testing and treatments are viable<br />
substitutes <strong>for</strong> field inspection when field<br />
inspection is not possible.
Thank You!<br />
rdunkle@amseed.org