Some may rarely think of how fruits and vegetables end up at dinner in one piece. Some growers worry about this – literally. In watermelon production, researchers and growers know something is wrong when a rotting watermelon ruptures open with a loud, popping noise.

The culprit is almost always bacterial fruit blotch, especially in Georgia. The bacterium infects watermelon and other melons and gourds.

“I had a watermelon rupture near my foot once,” said David Langston, associate professor of plant pathology. “It startled me a bit because it was so loud.”

Rupturing watermelons are actually a side effect of the bacterium. When the fruit is infected, the bacteria feed on the fleshy inside, producing gases. With a warm day, pressure builds up inside of the watermelon until it ruptures.

With the struggling peanut market, more people are growing watermelons – there will be more grown this year than ever before in Georgia, Langston said. Monitoring watermelon seedlings and plants is important to reduce crop losses, he said.

Plant pathologist Ronald Walcott also studies bacterial fruit blotch. His research looks at how the bacterium spreads.

The bacterium can be deposited in the ovary of a watermelon by insects, Walcott said. As a result, the seeds produced by that watermelon are infested.

Walcott, alongside doctoral student Kameka Johnson, looks at the mechanisms the bacterium uses. They have studied how seeds become infected through the ovary of the watermelon and how signaling through quorum sensing – a way bacteria communicate to express genes – shapes the bacteria’s behavior.

Walcott and Johnson’s goal is to figure out how to alter the bacteria signals.

“It’s strange because the bacteria stay dormant in the seed until the seed starts to grow,” Walcott said. “We are trying to find ways to trick or stop these cues.”

He explained disrupting these signals is similar to a malfunctioning gun, even if it is loaded with bullets.

The strain of bacterial fruit blotch found in Georgia can wipe out entire greenhouses or fields. Langston said growers can lose nearly $6,800 per acre of watermelon grown, and there have been two cases reported in Colquitt County this year.

“To me, fruit blotch is already a big problem because we still see it,” Langston said. Educating seed growers and watermelon producers will prevent large scale losses each June when watermelons are harvested.

Langston and Walcott advise people who handle plants with fruit blotch to be careful not to spread it to other plants via clothing or shoes.

Fortunately, bacterial fruit blotch can be properly managed if caught early. Seeds and plants can be treated with copper, antimicrobial treatments and antibiotics, Walcott said. In the case of an outbreak, Georgia Department of Agriculture professionals secure the greenhouse, wash down the inside with a disinfestant and dispose of or burn the infected crops, Langston said.

Many seed companies outsource beyond U.S. borders because labor costs are cheaper, Walcott said.

“Since the pathogen can be transferred through seeds, it’s a controversial issue because most producers import seeds from parts of Asia and South America,” he said. “There are a lot of lawsuits between growers, transplant producers and seed companies.”