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Animal and Plant Health Inspection Service
U.S. Department of Agriculture
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Potentially Actionable Suspect Sample Policy: Candidatus Liberibacter asiaticus causative agent for Citrus Greening (CG)/Huanglongbing (HLB)

Overview

A Potentially Actionable Suspect Sample (PASS) is a regulatory sample3 from the environment or an APHIS approved exclusionary facility5 where preliminary diagnostics indicate Candidatus Liberibacter asiaticus, a USDA regulated pathogen, is present and requires confirmation by the USDA-APHIS-PPQ-S&T, Plant Pathogen Confirmatory Diagnostics Laboratory (PPDCL).

Samples Collected from a Non-Regulated Area

Any regulatory sample collected from a non-regulated area1 or an APHIS approved exclusionary facility that tests positive for the presence of Candidatus Liberibacter asiaticus by a NPPLAP accredited lab6 using an APHIS approved screening test is considered a PASS and must be forwarded to the USDA-APHIS-PPQ-S&T PPCDL for final determination. Sample4 should consist of symptomatic plant material.

Sample Diagnostics
USDA APHIS PPQ Science & Technology
Plant Pathogen Confirmatory Diagnostics Laboratory PPCDL
9901 Powder Mill Rd. Bldg. 580
Laurel, MD 20708
Phone: (301) 313-9208 or 9271

When forwarding materials notify the lab at: APHIS-PPQCPHSTBeltsvilleSampleDiagnostics@usda.gov you must include number of samples, screening diagnostic results and tracking information in this communication. Do not ship samples on Fridays or the day before a federal holiday.

Additional information for preparation and submission of samples can be found at Request Official Confirmation of Preliminary Pest Identifications of Domestic Samples

Samples Collected from a Regulated Area

A regulatory sample collected in a regulated area2 where preliminary diagnostics indicate Candidatus Liberibacter asiaticus by a NPPLAP accredited lab using the APHIS approved screening test is considered a PASS and must be forwarded to the USDA-APHIS-PPQ-S&T PPDCL laboratory for final determination ONLY under the following conditions:

  • The sample is an unusual detection (novel symptoms or new host) and/or
  • The sample will result in the expansion of a previously established regulated area

A NPPLAP certified analyst at a NPPLAP accredited laboratory has the authority to make the final determination on a regulatory sample collected from a regulated area (previously confirmed positive by APHIS PPQ S&T) if:

  • The laboratory notifies the APHIS national or regional program manager of the positive within 24 hours of the diagnostic result.

Definitions

1 Non-Regulated Area: Any area where CG/HLB is not known to occur in the United States.

2 Regulated Area: Any APHIS recognized area where CG/HLB has been federally confirmed.

3 Regulatory Sample: This is a sample of regulatory concern to APHIS for CG/HLB collected by regulatory officials.

4 Sample: A sample refers to a single bag of leaves or a twig with attached leaves. Each sample is to contain a minimum of 12 symptomatic (unhealthy) leaves; 12-16 leaves if possible. It is strongly encouraged that each sample is from one plant.

5 APHIS approved exclusionary facility: A greenhouse structure designed to exclude quarantine pests that is approved by APHIS to produce citrus nursey stock for interstate movement.

6 NPPLAP Accredited Lab: A laboratory recognized by APHIS through the National Plant Protection Laboratory Accreditation Program as possessing all the necessary equipment and certified personnel to perform CG screening tests using the current APHIS work instructions.

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