Maine’s Bureau of Pesticides Control will determine next month whether to approve the registration of a type of genetically modified corn in Maine.

Maine is the only state in the country where the corn, known as Bt, for Bacillus thuringiensis, corn cannot be grown or sold.

John Jemison, a crop scientist at the University of Maine in Orono, is chairman of the board committee that has been investigating Bt use.

“Basically, the interest for this came from large-herd dairy farmers who have lots of acreage and plant lots of corn,” Jemison said Friday.

Jemison said that in light of the fact that many other genetically altered crops are grown and sold in Maine, the board is responding to a request filed in March by three biotech companies – Dow AgroSciences, Pioneer Hi-Bred International and Monsanto – on behalf of dozens of Maine farmers.

The companies submitted applications to register seven Bt field corn products, used as feed for animals.

Bt corn has been genetically modified to produce plant-incorporated protectants, in this case the pesticidal proteins from the naturally occurring soil-borne Bt bacteria that kill certain insects.

With corn, the target insects are caterpillars and soils pests such as cutworms and rootworms, according to the board. This makes Bt corn a pesticide and, in Maine, all pesticides must be registered and approved by the BPC before they can be sold or used.

The history of Bt corn in Maine began in 1994, when the BPC undertook technical reviews to look for adverse effects on human health and for the potential development of insect resistance.

According to Jemison, these reviews were conducted in 1997 after receipt of applications to register three Bt corn products. The human health review concluded there were no concerns, and a process was established to identify any development of insect resistance. However, the registrations were denied because Maine’s pesticide statute requires that there be a demonstrated need or benefit for the products, and there was no such information available at that time.

Jemison said the farmers have made inquiries about Bt corn for a decade but only in the past five months have registration requests been pursued by the three chemical companies. In the interim, the board has been gathering information at each of its meetings on topics such as economic need, and a technical advisory committee was established to evaluate the potential for pollen drift and resistance issues.

At these meetings, Jemison said, supporters claimed that Bt corn reduces pesticide use, increases yield and requires fewer trips through the field. They also stated that the highest-yielding varieties are now available only as Bt corn and that Maine is at a disadvantage compared with the rest of the country.

Opponents, however, expressed concern about insects developing resistance to Bt, since, in spray form, Bt is an important tool for organic growers. Other concerns mentioned were the potential contamination of non-Bt corn crops from pollen drift and liability issues when non-Bt crops are contaminated.

The Board of Pesticides Control will meet at 9:30 a.m. Friday, July 27, at the Hampton Inn in Waterville. The meeting will be open to the public but is not a formal public hearing.