Exploding Watermelon Perplexes China

Chinese farmers are scratching their heads after fields of watermelons turned into exploding land mines. The official cause remains unknown but some believe that the farmers sprayed a rapid growth chemical on the fruit too late in the season and after an extremely wet period. The combination of factors could lead to exploding fruit, as the cells expand so rapidly the fruit bursts out of its rind.

State-run Chinese TV reports that acres of watermelons have been destroyed by the mysterious fruit explosions.

In China the chemical forcholorfenuron is commonly used to give fruits a burst of growth. The chemical is only approved for use on kiwis and grapes in the United States. But using the chemical incorrectly can cause problems — like exploding watermelons.

In 2004 the Environmental Protection Agency added forcholorfenuron to a list of newly created pesticides. The agency classified the growth accelerator as a phenyl urea compound but found that it is unlikely carcinogenic in humans. Due to the small amounts required to accelerate fruit growth, the agency decided to approve the chemical.

Though it did include a warning.

“The Agency‘s major concern is forchlorfenuron‘s persistence and its possible chronic effects to terrestrial organisms. It is highly persistent in the environment with laboratory half-lives ranging from 226-578 days in terrestrial environments and stable in aquatic environments. While forchlorfenuron rapidly photodegrades in sensitized water, the Agency does not believe that this route of dissipation is significant in the environment. Suspended sediment and shading prevent photodegradation.”

This plant growth regulator should be used two to three weeks after bloom. If applied properly (in low amounts) Forchlorfenuron results in an increase in fruit size, but does not affect the number of fruit or the keeping quality of the fruit.

Farmer error is likely behind the Chinese exploding watermelons. Although some Chinese officials say that the seeds, which were imported from Japan, might be the culprit. In ten fields, farmers who claimed not to use forchlorfenuron also experienced combustible fruit.