In this photo taken Sept. 10, 2014, Monsanto crew members Gerard Manuel, left, and Rommel Angale, right, count corn sprouts in a field of test hybrids in a breeding nursery near Kihei, Hawaii. Maui County voters will decide in the next few weeks whether to ban the cultivation of genetically engineered organisms, at least temporarily. A "yes" vote on the Nov. 4 ballot initiative would require large multinational companies that research new varieties of corn and soybeans in Maui to stop farming until they are able to prove their methods are safe. This could upend global agriculture giant Monsanto's research pipeline for new varieties of corn and soybeans. (AP Photo/The Maui News, Matthew Thayer)

Groups are campaigning in Maui County over a Nov. 4 ballot measure that would prohibit the growing of genetically modified organisms until studies show they're safe.

Their dueling efforts show it isn't just a local issue in a county of only 160,000 residents in the middle of the Pacific Ocean.

Experts say the ban's effects could ripple across the nation because some of the world's largest corn-seed producers research and develop new varieties of genetically engineered seeds at their farms in the county.

Dozens of Maui mothers are going door-to-door to urge voters to back a ban on the cultivation of genetically engineered crops because they think they are unsafe.

A group backed by companies growing the crops counters with ads urging rejection of what they call a "farming ban."

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