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5. Guidelines for Seed Samples for Nematode Detection

Nematology Laboratory

Guidelines for Seed Samples for Nematode Detection:

• For nematodes, all samples must be collected by the local county Agricultural inspector only. All samples mustbe sent to the CDFA nematology laboratory in Sacramento, accompanied with the appropriate and duly filled Plant and Pest Detection Report form hard copy. A printed hard copy of the PDR must be sent with the sample after the information has been entered in the computer by the submitter. Samples not accompanied with a PDR form will be subject to rejection or may greatly delay the diagnosticprocess by the Lab.
• Determine shipment size in order to determine sample size. Sampling seed for the possible detection of nematodes is based on the actual shipment size for export, and not number of seeds. For total shipment sizes of 300-500 g or less, a composite sample of 1-5% of the shipment size is collected. For larger shipment sizes, such as is commonly encountered in onion and alfalfa seed shipments, a minimumcomposite of 300-500 g is required.
• Sample collection. Several subsamples are collected from the top, middle and bottom levels of the seed container/storage facility. At each level, three to four 300 g subsamples are collected from the outer periphery, mid point and central point. Subsamples are collected in a large bucket. Thetotal collectionmay result in several kilograms of seed. These seeds are thoroughly mixed in the bucket and from this well-mixed lot the appropriate samples size is collected for lab assay. Sample collection is similar for small (containerized) and large shipment sizes, however the size of subsamples collected at each level will differ.
• Mailing. Seeds are sent to CDFA-PPD’s Nematology Laboratory in durable plastic bags. Each bag must be labeled with the appropriate sample (PDR) number on the outside of the bag.
• Do not send seeds that have been chemically treated. These will be rejected by the Laboratory.
• Billing information. Indicate total shipment size and sample size on the PDR form. Also, for invoicing, include the name of the contact, address, phone and Fax numbers. The Fee for sample processing and nematode diagnostics is $40.00 per sample.
• Caution. Inappropriate sample size, inaccurate or absence of information/PDR forms may not only delay the process but also disqualify the sample for laboratory analysis.
• Please do not have the seed company contact the laboratory for results. The Laboratory will notify the county with results once ready.

Prepared by Dr. John Chitambar, May 2007.