Drug Summary & History
Diquat INAD 10-969

Anecdotal observations from fish culture facilities across the United States suggest that Diquat can be safe and effective when used to control mortality in a variety of fishes diagnosed with bacterial gill disease (BGD) or external flavobacteriosis. For example, typical treatment regimens for coolwater and warmwater fishes have included immersion treatment at 6 - 28 mg/L for 1 - 4 h. In addition, Diquat has been used to treat salmonids at 2 - 10 mg/L for 1 -2 h. Such anecdotal observations are supported by data collected under Diquat INAD 8110, which has been held by the State of Illinois since the mid 1980's. Although INAD 8110 is no longer “active” and available for use, Diquat may now be used under USFWS INAD #10-969.

The primary goal of field studies conducted under INAD #10-969 is to generate data to help determine appropriate Diquat treatment regimens for controlling mortality in a variety of cultured fishes diagnosed with BGD or external flavobacteriosis. Syngenta Crop Protection, Inc., will be the sole supplier of Diquat to all Investigators. Under this INAD, two treatment regimens will be allowed (see options A and B below), and withdrawal time will vary with species and treatment regimen. No prophylactic or preventive use of Diquat is allowed under this INAD.

Treatment Option A: Administer as an immersion static-bath or flow through treatment at 2 -18 mg/L for 1 - 4 times for 1 - 4 h each time. Up to four treatments may be administered on consecutive or alternate days.

Treatment Option B: Administer as an immersion static-bath or flow through treatment at 19 -28 mg/L for 1 - 3 times for 30 - 60 min each time. Up to three treatments may be administered on consecutive days.