Refuge Requirements for Bt Cotton

Refugia acreage (non-Bt cotton) will provide a source of susceptible moths for mating with resistant moths that survive in Bt cotton.  Designated refugia acreage should be located adjacent to or in close proximity of Bt-cotton acreage.  The refuge should be managed with the intent of producing a viable, vigorous crop. 

Refuge guidelines allow a producer to select among several refuge options.  The information below is intended only as a summary of these options.  Please refer to the grower licensing agreement and refuge guidelines (Bollgard Refuge Guide) provided by the company for complete details.  The following website describes in greater detail the various refugia plans, IRM Guides. 

Option 1 requires a 20 percent or greater acreage planted to non-Bt cotton.  This acreage can be treated with conventional insecticides, except foliar Bt products, to control all caterpillar species as well as other pests.  All Bt fields must be within one mile, but preferably one half mile, of the refuge field. 

Option 2 is a 5 percent non-Bt refuge that can not be treated for bollworm or tobacco budworm.  The refuge must be 150 feet wide, and all Bt fields must be within one half mile of the refuge.  This refuge acreage should not be treated with insecticides that control caterpillar pests.  Non-caterpillar pests should be treated according to treatment thresholds, but there are restrictions on the kinds and rates of insecticides that can be used (see current licensing agreement). 

Option 3 is a 5 percent non-Bt, embedded refuge that can be treated for bollworm and tobacco budworm only when Bt fields are also treated.  If the embedded refuge is treated for bollworm or tobacco budworm, the associated Bollgard field or field unit must be treated at the same time with the same treatment.  Foliar Bt products can not be used on the refuge.  The refuge must be part of a field or field unit and at least 150 feet wide.  A “field unit” is defined as any group of fields that are contained within a one mile square (one mile by one mile) area. 

A fourth option is the Community Refuge Plan.  Details about this option are available at the above websites.