Fish and Aquatic Conservation

Diquat® INAD #10-969

Photo of a Walleye
Credit: Eric Engbretson, /USFWS


Reward® (DQT) is a liquid concentrate containing diquat dibromide that is applied as an immersion bath treatment. DQT is available for purchase through many local farm & ranch stores or through Syngenta Crop Protection, LLC. The primary goal of field studies conducted under INAD #10-969 is to evaluate the efficacy of DQT for controlling mortality in all freshwater-reared finfish diagnosed with BGD or external flavobacteriosis. The treatment regimens allowed for DQT immersion are 1) 2 – 18 mg/L for 1 – 4 hours for 1 – 4 days; or 2) 19 – 28 mg/L for 0.5 – 1 hour for 1 – 3 days. The Investigational withdrawal period for DQT for adult Ictaluridae and Esocidae is 5 days; all other freshwater-reared finfish have a 30 day Investigational withdrawal period. The investigational Investigational withdrawal periods can be incorporated into the grow-out period. No prophylactic or preventive use of Diquat is allowed under this INAD. To participate in the INAD Program for DQT visit the data collecting site.

Please read the Study Protocol prior to any treatments. It contains the protocol, MSDS, and a copy of the forms to be used as a guide for collecting data that will be entered into the online INAD database. The FDA authorization letter(s) for this INAD is currently only available by emailing Bonnie Johnson.

INAD objective/purpose: Collect supportive and/or pivotal data needed to establish the effectiveness of diquat to control mortality caused by certain bacterial diseases.

Drug Name
Diquat (Reward®)

Drug Source
Syngenta Crop Protection, LLC (often available from your local farm & ranch store, veterinary supply outlet, etc.)
P.O. Box 18300
Greensboro, NC 27419-8300

Turf Landscape and Pest Customer Service
Phone: 1-866-SYNGENTA (796-4368-2)

Target pathogen(s): External flavobacteriosis (e.g. bacteria responsible for bacterial gill disease and external columnaris)

Method of administration: Immersion: flow-through or standing bath treatment

Treatment dosage:

  • Option A: 2-18 milligram (mg) diquat per liter
  • Option B: 19-28 milligram (mg) diquat per liter

Treatment regimen:

  • Option A: 1-4 hour treatment; 1-4 treatments on alternate or consecutive days
  • Option B: 30-60 minute treatment; 1-3 treatments on consecutive days

Investigational Withdrawal period:

  • 5 days for adult Ictaluridae and Esocidae.
  • 30 days for all other fish species.
  • No holding time is assigned for fish that have a grow-out period that exceeds 30 days. The investigational withdrawal periods may be incorporated into the grow-out period.

Required test parameters:

  • Investigator must collect mortality data throughout the 5 day pre-treatment, treatment, and 10 day post-treatment periods. Investigator should also report general fish behavior and any adverse effects relating to treatment.

Limitations or restrictions on use of drug:

  • Prophylactic (preventive) treatment of fish is not allowed.
  • Investigator must follow all instructions in the Study Protocol for INAD 10-969 regarding drug acquisition and handling, fish treatment and disposition, and data reporting requirements.
  • Drug discharge must be in compliance with local NPDES permitting requirements.

Required INAD fee: $700/facility/year

AADAP Contact Information:
Ms. Bonnie Johnson, FWS-AADAP
Phone: 406-994-9905
Fax: 406-582-0242