Bt corn continues to perform as well and possibly even better than normal elite commercial hybrids available in Wisconsin (see the last issue of the Wisconsin Crop Manager). It is a technology that improves yield and quality and helps farmers control damaging insect pests including European corn borer. The following article is derived from the website: http://www.ncga.com/biotechnology/insectMgmtPlan/importance_bt.htm

To preserve the benefits of Bt corn technology the planting of a non-Bt refuge is recommended. All Bt corn products designed to control European corn borer, southwestern corn borer and corn earworm are required to have a non-Bt refuge. Growers who fail to follow these requirements risk losing access to Bt corn technology. In order to maximize the effectiveness of the refuge, you should manage your non-Bt corn and Bt corn in a similar manner by 1) planting your non-Bt corn as close to and at the same time as your Bt corn, and 2) selecting non-Bt hybrids and Bt hybrids that have similar growth and development characteristics.

Refuge Size Requirements

Your corn growing area must have at least at least 20% refuge. A non-Bt refuge must be planted within 1/2 mile of each Bt corn field, but preferably within 1/4 mile.

Refuge Planting Options The appropriate size non-Bt corn refuge may be planted a number of ways: = Bt corn field, = Non-Bt refuge, = Soybeans
Block Refuge (Adjacent) A block of non-Bt corn adjacent to the Bt corn field	Block Refuge (Within) A block of non-Bt corn within the Bt corn field	Refuge Perimeter Non-Bt corn surrounding Bt corn field	Split Planter Refuge Strips of non-Bt corn at least 4 rows wide with the Bt corn field (6 rows preferred)	Pivot Corners Refuge Non-Bt corn in pivot corners within the Bt corn field	Separate Field Refuge A separate field of non-Bt corn within 1/2 mile of the Bt corn field (1/4 mile preferred)

Insecticide Usage in Non-Bt Refuges

In non-Bt corn refuges conventional insecticides can be applied ONLY if target pest pressure reaches economic thresholds. Bt-based foliar insecticides are NOT to be used within the refuge.