Growers throughout the country this year have benefited from the broad-spectrum insect control delivered by hybrids with the HERCULEX® family of traits. Hybrids with HERCULEX offer powerful in-plant protection that gives growers excellent, valuable insect control with less labor, stress and worry.

However, access to in-plant insect protection technology comes with great responsibility. Product stewardship of all HERCULEX products is vital, and starts with reviewing, understanding and remaining current with regulations.

Compliance with Insect Resistance Management (IRM) requirements is important to the long-term success of all Bt trait products because IRM programs are designed to delay the onset of resistance. A key element in IRM is the use of a refuge. Refuge areas work because they allow for susceptible-type insects to develop and flourish; they increase the potential for mating between susceptible and resistant types and allow for the decrease of resistant genes in the population.

HERCULEX I Insect Protection

Growers must plant a refuge of at least 20 percent non-corn borer resistant Bt corn within ½ mile of the HERCULEX I corn. The refuge may be planted in a variety of configurations within fields or in separate fields. You CANNOT use YieldGard Bt hybrids as a refuge for Herculex I hybrids.

HERCULEX® RW Rootworm Protection

When planting hybrids with HERCULEX RW, growers must have refuge acres in all areas, including the Corn Belt and in cotton-growing areas. Growers can plant up to 80 percent of corn acres with Bt corn rootworm protected hybrids, but 20 percent of their corn acres must be non-Bt corn or non-corn rootworm resistant Bt corn refuge. Again, you CANNOT use YieldGard RW products as a refuge for Herculex RW products.

Refuge areas can be within or adjacent to the Bt field, but adjacent refuge fields must be owned or managed by the same grower. Use of a neighbor’s field to meet the refuge requirements is not permitted. There is some flexibility when designing refuge acres; they may be square fields, blocks within a field and strips across the fields. Refuge areas planted as strips must be at least four rows wide.

When using HERCULEX RW, refuge corn can be treated for larval corn rootworm and/or other soil pests with soil- or seed-applied insecticides. Aerially applied insecticides that are labeled for corn rootworm control may be applied on the refuge when adult rootworms are present only if the same treatments are used on the HERCULEX RW corn area. This applies to treatments targeted at adult rootworms or at other pests.

HERCULEX XTRA Insect Protection

When planting HERCULEX® XTRA Insect Protection, growers have two refuge options available: common refuge and separate refuge. The simplest option is a common refuge that is designed to provide refuge for both corn borers and corn rootworms. However, separate refuges for each type of pest are permitted, allowing greater flexibility than the common refuge.

Common refuge option: Requirements and guidelines

In the Corn Belt, growers may plant up to 80 percent of their corn acres with HERCULEX XTRA corn, but 20 percent of the corn acres must then be planted with non-Bt corn. If planting more than one brand of Bt corn that is resistant to both corn borers and corn rootworms, growers must ensure that at least 20 percent of their total acres are planted with non-Bt corn.

The common refuge can be separated by a ditch or road, but not another field. Refuge placement options include adjacent fields, blocks within fields and strips across the fields. Adjacent refuge fields must be owned or managed by the grower. Use of a neighbor’s field will not satisfy the refuge requirement.

The common refuge can be treated for corn rootworm larvae and other pests with soil- or seed-applied insecticides. Late-season pests can be treated with insecticides that are not labeled for adult corn rootworms, unless treatment occurs when adult corn rootworms are not present. If adult corn rootworms are present, the same treatment must be applied to the refuge and all corn rootworm Bt acres.

Separate refuge option: Requirements and guidelines

Separate refuges are designed to work independently for corn borers and corn rootworms. That is, the refuge for corn borers, which can contain a trait for corn rootworm protection, is planted separately from the refuge for corn rootworms, which can contain a trait for corn borer protection.

Corn borer refuge: In non-cotton growing areas, growers can plant up to 80 percent of their corn acres with hybrids resistant to corn borer, but they must plant 20 percent of corn acres with a hybrid that does not contain a Bt trait specifically for control of corn borer.

Corn rootworm refuge: In both the Corn Belt and cotton-growing areas, up to 80 percent of corn acres may be planted with hybrids resistant to corn rootworm and at least 20 percent of corn acres must be planted with a hybrid that does not contain a Bt trait specifically for control of corn rootworm.

Plant the corn rootworm refuge within, or adjacent to, each field planted with HERCULEX XTRA. The rootworm refuge can be separated by a ditch or road, but not another field.

Late-season pests in the corn rootworm refuge can be treated with insecticides that are not labeled for adult corn rootworms. Insecticides labeled for adult corn rootworms may be used on the corn rootworm refuge only if treatment occurs when adult corn rootworms are not present.

To ensure that growers comply with all IRM requirements, the U.S. Environmental Protection Agency and the Agricultural Biotechnology Stewardship Technical Committee have instituted an IRM Compliance Assurance Program. Under the IRM Compliance Assurance Program, growers who do not follow the IRM requirements may be denied access to Bt corn hybrids. For more information on IRM requirements, contact your local seed provider or visit www.herculex.net for the most current Product Use Guide.

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