AUGUSTA — The state’s pesticide control board has agreed to add two new Bt-corn products to the list of genetically engineered seeds grown in Maine.

Maine now allows 21 Bt products with insecticidal genetic traits to be planted in fields now that Pioneer Hi-Bred International, a multinational biotech company and subsidiary of DuPont, won a bid to register its two new Bacillus thuringiensis corn here.

In August, DuPont received approval from the U.S. Environmental Protection Agency for the registration for Optimum AcreMax and Optimum AcreMax Xtra insect protection products in corn. The products are seed-blended and considered refuge in a bag, which allows farmers no longer to plant a separate refuge area around fields in corn-growing areas.

A refuge refers to corn that does not contain the Bt-toxin and allows the pest to complete its development.

The board voted 6-1 Dec. 16 to approve registration of the two new products.

In 2008, Jemison said, the board first approved the use of Bt corn in Maine. The board approved Bt potatoes in the 1990s, he said.

Optimum AcreMax marks the industry’s first U.S. approval of a single-bag integrated refuge product that targets only above-ground insects. OptimumAcreMax Xtra insect protection is a single-bag refuge product targeting above- and below-ground insects.

John Jemison, Jr., who serves on the Maine Board of Pesticide Control and is a water and soil specialist with the University of Maine Cooperative Extension, headed up the board’s technical advisory committee that looked into these two new products. Jemison said his group spent a long time working on this decision.

“Ultimately for us, it came down to one point,” he said. “We know for sure the best way to develop resistance is to not plant a refuge. It’s conceivable that a grower might not plant a refuge; however, it’s not really easy to buy and plant only Bt corn in a given set of fields. I made it a big part of my program to go out and make sure they understood why the refuge is important.”

He said farmers who grew Bt corn were required to grow non-Bt crops on 20 percent of their farm as a refuge for normal insects. That way, the resistant insects probably would find nonresistant mates, instead of each other, and their offspring still would be killed by the Bt corn.

He said the approach approved by EPA was a fairly difficult and time-consuming requirement for growers. He understood their dislike of it but said the requirement allowed them to test the effectiveness of the technology in the field where the Bt products are planted.

However, the seed companies have not done their diligence to ensure growers are complying with the approach, Jemison said, and that the pesticide control board doesn’t have the staff to follow up with all growers using the technology.

A recent article the journal PLoS One — “Insects Find Crack In Biotech Corn’s Armor” — says a new generation of insect larvae appears to be “munching happily on the roots of genetically engineered corn.” The article says it’s bad news for corn farmers who paid extra money for Bt corn and bad news for the biotech companies such as Monsanto, that insert the larvae-killing gene in the first place.

Jemison said Western corn rootworm is not well controlled by Bt — at least not as well as the moth-pests are controlled by Bt.

Jamison said the majority of rootworms found in Maine are northern corn rootworms. He strongly recommends that farmers not use Bt to control those rootworms, because the damage they cause is minor.

Mechele Cooper — 621-5663

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