Prevention Requires Diligent Testing

- John Mizicko

Until 2013, cucumber green mottle mosaic virus (CGMMV)  — a quarantined pathogen for the United States — had never been found in the U.S., but that year it was found in a Yolo County, California, melon seed production field.

A common problem for Europe, Asia and the Middle East, the virus can be devastating and is easily spread. CGMMV affects watermelon, melon, cucumber, pumpkin, squash and gourds and threatens the fresh market, export and cucurbit seed industries. The virus can be introduced in many ways, including contaminated seed and soil.

In 2014, the virus was found again in U.S. commercial watermelon fields in two counties in central California, and those in the industry were on high alert. Fortunately, CGMMV has not been found in the U.S. in 2015 or 2016.

When the virus broke out, the U.S. adopted a seed testing regime from the International Seed Testing Association and it was also adopted by the National Seed Health System (administered by the U.S. Department of Agriculture and Iowa State University). It’s an ELISA (enzyme linked immunosorbent assay) test for CGMMV.

But the important thing for companies, regardless of size, producing cucurbit seed or sourcing cucurbit seed from outside the U.S., it needs to be tested for this virus. It’s extremely important for companies to follow protocol and have the seed tested prior to any of it being planted in the United States.

Government officials and the seed industry as a whole don’t want the virus to get established and become endemic, especially in seed production areas, as it could have a devastating impact … on commercial production, too.

To help, USDA’s Animal and Plant Health Inspection Service has developed the National Seed Health Accreditation Pilot Program (NSHAPP), which is a voluntary accreditation program. As part of the program, companies that sign up commit to have their seed tested by an accredited laboratory, report any positive lots to USDA and destroy any seed lots found to be positive.

Any company that handles or imports cucurbit seed is urged to participate. The program is not designed to be overly cumbersome, but the goal is to work together to keep infected lots from coming into the United States.

To date, six companies have volunteered to participate. These include Bayer Vegetable Seeds, Enza Zaden, HM.CLAUSE, Keithly-Williams Seeds, Rijk Zwaan and Sakata Seed. If you’re involved in cucurbit seed, I encourage you to learn more about the program at