Alexandria, Virginia, USA
November 26, 2012

Source: Newsletter of the American Seed Trade Association (ASTA)

Companies that produce and import spinach seed into the US from Europe are now confronted with a new problem: Phomopsis. In 2011 a large shipment of spinach seed was rejected entry due to a detection of a species of Phomopsis by Customs and Border Protection and USDA APHIS officials. However, in 2012, at least 10 additional shipments have been rejected entry due to detections of this organism. Spinach seed is a high-value product; individual shipments range in value from $750,000 to over $ 1 million each. The value of the spinach seed market in the fall is in the range of $12 to $20 million. Leafy spinach is produced almost year-round on the west coast, mostly in the states of California and Washington, and these growers depend on seed provided by ASTA member companies that produce and import this seed from the Netherlands and Denmark.

Phomopsis on spinach seed is a new phenomenon. There are no evidences that this organism is pathogenic on spinach; however, because this genus contains species that are pathogenic on other species such as soybeans and sunflower, APHIS is treating this organism as a quarantine pest at least until its phytosanitary risk can be determined. The trigger for inspectors at the ports of entry is the visible presence of small black speckles on the surfaces of seeds, believed to be the pycnidia, or fruiting bodies, of the fungus. If black speckles are present, inspectors take seed samples and provide them to APHIS pathologists who then make the official determinations. APHIS scientists have also been conducting genetic studies in which they sequence the DNA and compare these sequences to those that are in the official US collection, which is the largest in the world. The sequence from the 2011 interception did not match up to anything in this collection, indicating that it is a species either not represented in the collection or it is a species new to science. Sequences form 2012 interceptions match up with isolates of European origin. The latest information on the identification of this organism by APHIS is that it is the asexual form of Diaporthe (Phomposis) viticola, which occurs throughout Europe and is pathogenic on grape vines and blueberries. The asexual form is not known to occur in the US.

What has ASTA been doing in response to this problem? ASTA has been sponsoring numerous conference calls for concerned members with USDA APHIS and the academic community to communicate issues and concerns and exchange information. In addition, ASTA has been maintaining close communication with European stakeholders including ISF, European Seed Association, Plantum, Naktinbouw, and European seed companies. ASTA encouraged Dr. Lindsey DuToit, a prominent research seed pathologist located at Washington State University to submit a research proposal to address the issues identified by APHIS, as well as to identify an effective phytosanitary treatment. ASTA members recently made the decision to fund this proposal out of the ASTA emergency brush fire fund. This research will begin as soon as the protocols for evaluating treatments and pathogenicity have been reviewed and approved by APHIS, as the results will be used by APHIS to make future regulatory decisions concerning this organism. For more information, contact Ric Dunkle at rdunkle@amseed.org.
 

Website: http://www.betterseed.org/

Published: November 26, 2012