Organic Sweet Corn

"Zea-later!" Organic Corn Treatment Spells End to Wormy Ears

Vegetable grower Steve Mong of Stow, Mass., uses a newly patented Zea-later to apply corn oil and Bacillus thuringiensis (Bt) to the top of an ear to control corn earworms. “Sweet corn is one of the top money-makers for the farm,” he says. Photo by Ruth Hazzard.

A widespread sweet corn pest, corn earworm moths seek the sweet odor of corn silk to lay their eggs, prompting producers nationwide to accept wormy corn or apply broad-spectrum pesticides three to 10 times per crop. Organic growers, in particular, are forced to offer one of their most profitable summer crops complete with extra, unwanted protein. “When the earworm hit, sales would drop considerably,” said Steve Mong, a Stow, Mass., vegetable grower. “We would leave a knife on the table so anyone who didn’t want to take a worm home with them could cut it out.”

Now, thanks to work headed by SARE-funded researcher Ruth Hazzard at the University of Massachusetts, Mong and other growers use new, effective biological controls to fight the earworm—corn oil and Bacillus thuringiensis (Bt). Hazzard’s technique, a practice that evolved over a decade, calls for applying Bt and corn oil to the top of each ear during the formative stage, causing earworms that crawl into the ear to suffocate.

In collaborative research at the University of Massachusetts, Anne Carter found that just one treatment will keep working until harvest. Eight farmers from Vermont to Connecticut found that the oil controlled ear damage in 83 percent of their trial plots in 2000. The idea came from a grower participating in a SARE-funded forum 10 years ago; his neighbor had applied mineral oil to control earworm in the 1940s. “We’ve taken the concept and brought in new, safer materials,” Hazzard said.

To cut down on labor costs, Hazzard worked with students from Hampshire College and her university to invent a hand-held oil applicator, patent it and find a manufacturer. The well-respected Johnny’s Selected Seeds catalogue company offers the product and moved 50 off the shelves the first year. Dubbed the Zea-later, the device cuts the labor involved to about eight hours an acre, meaning a grower with 10 acres of sweet corn could handle the job over a few days, then find himself worm-free for the entire season.

[For more information, go to www.sare. org/projects/ and search for LNE99-118]

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