The goal of the National Seed Health Accreditation Pilot Program (NSHAPP) is to develop a model for a voluntary system of testing seed imported into the USA for pathogens of phytosanitary concern. In response to detection of foreign pathogens in the US, USDA-APHIS has partnered with the seed industry to screen imported seed with diagnostic testing to prevent the introduction of seed-transmitted pathogens. The cucurbit pathogen Cucumber green mottle mosaic virus (CGMMV) will serve as the first pathogen to be tested under this program. Imported cucumber, melon and watermelon seeds will be screened for the pathogen.

More information on CGMMV was compiled by the American Seed Trade Association and can be found here:

CGMMV Brochure – American Seed Trade Association

Participating Companies
CGMMV Brochure


Who may participate

  • Seed importers who are bringing shipments of cucumber or melon seed in to the U.S., and have the capability for CGMMV testing:
    • Companies that are accredited by the National Seed Health System (NSHS) or Naktuinbouw (NAL) may utilize their own accredited laboratory for seed health testing.
    • Companies without appropriate accreditation may utilize outside laboratories that are recognized under the NSHAPP for CGMMV testing accreditation. A list of recognized laboratories will be available.

NSHAPP Participation Requirements and Compliance Agreement

To participate in the program, companies must provide a copy of their lab’s accreditation or identify the accredited lab they will be using for sample testing, and a written description of the seed disposal method they will use in the case of a positive find to the National Seed Health Coordinator at APHIS.  The National Seed Health Coordinator will work with the company and local APHIS personnel to enroll the company in the program. The signed compliance agreement may be signed, scanned, and emailed or mailed to the National Seed Health Coordinator.

CGMMV Method

The method for testing that must be followed by all participants and accredited labs is Cb 3.1 ISTA Assay 7-026 and is found here:

CGMMV Method

Treated seed is currently not allowed in the program as the established seed test for CGMMV is not validated for treated seed. Iowa State is working on validating a method for use on treated seed.

Data on small lots of seed will be accepted beginning March 1st, 2016. A small lot for this program is a lot containing less than 20,000 seeds. For small lots it has been agreed that a 5% sample is adequate. The sample must still be tested in 100 seed reps as described in the method. Reps containing less than 100 seeds can still be tested but records of sample size in the rep must be maintained. When recording data for small lot samples please indicate the size of the lot.

Data Collection

Participants will be required to maintain records with the following information for material being tested:

  • Species and variety of seed tested
  • Origin of seed
  • Number of seed lots tested
  • Number of positive seed lots

All relevant information about seed lots tested under the program should be maintained by each company for review by APHIS upon request. Summary reports must be provided to the National Seed Health System Administration at least once a month. When submitting monthly report data, please use this form when submitting monthly report data:

NSHAPP Data Submission Form

Any positive finds should be reported to the National Seed Health System Administration and USDA-APHIS immediately. All relevant information for a positive find should be reported, including:

  • Crop species
  • Crop variety
  • Unique seed lot identification number
  • Seed origin
  • Year produced
  • Testing location, date
  • Current location of impacted seed lot
  • Volume of positive seed lot
  • Customs # or phytosanitary certificate

The information will be used to immediately do a trace-forward and trace-back. Seed lots that test positive will be re-exported or destroyed. Several USDA destruction treatment options are available:

  • T415-a – Garbage: Incinerate to ash
  • T415-b – Dry heat: 212F for 30 minutes followed by burial in a landfill
  • T408-a – Dry heat: various time/temperature combinations above 230F
  • T408-b – Steam: 250F @15 pounds per square inch for 30 minutes

More information about the seed destruction methods can be found here:

Center for Plant Health Science and Technology

Participants may send seed to be tested at the Iowa State University Seed Science Center.  Sample size must conform to the ISTA method specifications. More information on the ISU Seed Science Center can be found here:

ISU Seed Lab

Contact information for NSHAPP program:

Gary Munkvold
NSHS Administrative Unit
160 Seed Science Center
Iowa State University
Ames, IA 50011
Tel: 515-294-7560
Ed Podleckis
National Seed Health Coordinator
Plant Health Programs
4700 River Road,
Riverdale, MD 20737
Tel: 301-851-2258