Growers who are concerned the watermelon seed they're buying is infected with watermelon fruit blotch may soon have a solution in the form of a new disease-detection test.


Scientists at the California Seed and Plant Health Lab Inc. in Elverta, Calif., have developed a new test that can detect watermelon fruit blotch in smaller trace amounts than previous tests, according to a news release.


In severe cases, the seedborne watermelon fruit blotch can reduce marketable yields by 90 percent.


Since only one or two seeds in a lot of thousands of seeds might be infected, sensitive tests are essential. Parm Randhawa and colleagues at the lab have developed a polymerase chain reaction, or PCR, test that can detect watermelon fruit blotch in watermelon and melon seeds.


The test also can determine whether the pathogen is alive or dead.


The PCR test magnifies the copies of the pathogen's DNA and copies it millions of times, making it easier to test for pathogen presence.


“In a blind test, the new test successfully detected the pathogen-infected seeds in 30 samples,” University of Georgia plant pathologist Ronald Walcott said in the release.

The researchers have successfully tested 1,925 lots of watermelon and melon seed during the past five years.


Watermelon fruit blotch was first identified in Florida in 1989. It has since spread throughout the United States.