Official Pest Report

Official Pest Reports are provided by National Plant Protection Organizations within the NAPPO region. These Pest Reports are intended to comply with the International Plant Protection Convention's Standard on Pest Reporting, endorsed by the Interim Commission on Phytosanitary Measures in March 2002.

Tilletia indica (Karnal Bunt): APHIS Reduces Regulated Areas in Maricopa and Pinal Counties in Arizona

Country: United States


Tilletia indica (Karnal Bunt): APHIS Reduces Regulated Areas in Maricopa and Pinal Counties in Arizona

Lynn Evans-Goldner, National Policy Manager, at or (301) 851-2286.


Effective immediately, the Animal and Plant Health Inspection Service (APHIS) is reducing the Karnal bunt regulated areas in Maricopa and Pinal Counties, Arizona. This is following a review of the results of the 2023 survey of Karnal bunt-regulated areas in Arizona.

Specifically, APHIS is removing three fields in Pinal County from the list of regulated areas because these fields meet the five-year cumulative tillage requirement included in the criteria for deregulation listed in 7 Code of Federal Regulations (CFR) § 301.89-3(e)(2).

In addition, APHIS is reducing the three-mile buffer area around positive fields in Maricopa and Pinal Counties to 0.2 miles based on an analysis APHIS completed on January 26, 2015. The analysis determined that a reduced buffer distance of 0.2 miles will provide the desired level of phytosanitary protection from Karnal bunt’s causal agent, Tilletia indica. APHIS did not implement the reduced buffer in 2015 because it was not operationally and administratively feasible to do so based on the number of fields regulated at the time. With the significant decrease in the number of infested fields since 2015, APHIS and the Arizona Department of Agriculture (AZDA) are now instituting the 0.2-mile buffer. This action to reduce the buffer is consistent with the regulations in 7 CFR 301.89-3(c). The buffer reduction will free multiple growers from quarantine requirements and relieve APHIS of continued monitoring in buffer fields that never had a positive Karnal bunt detection, without compromising safeguards against the spread of T. indica.

Due to the above changes, APHIS is removing a total of 36,982 field acres (835 fields) in Arizona from Karnal bunt regulation: 15,361 field acres (379 fields) in Maricopa County and 21,621 field acres (456 fields) in Pinal County, including 11,717 field acres (228 fields) on Ak-Chin Indian Community tribal land and 6,830 field acres (162 fields) on Salt River Pima-Maricopa Indian Community tribal lands. Accordingly, there are no more restrictions on the interstate movement of Karnal bunt-regulated articles from these areas; however, other portions of Maricopa and Pinal Counties remain regulated. AZDA has established a parallel state quarantine.

Karnal bunt is a fungal pest that affects wheat quality. APHIS regulates this plant disease because many trading partners require that U.S. wheat be certified as grown in areas free of Karnal bunt. We appreciate the cooperative relationship with the Ak-Chin Indian Community, the Salt River Pima-Maricopa Indian Community, the wheat industry and AZDA in the effort to limit the spread of Karnal bunt. APHIS will follow this action by publishing a notice in the Federal Register.

More information about the Karnal Bunt Program and federal Karnal bunt regulations is available at the following website: APHIS Karnal Bunt webpage.

Under IPPC standards, Tilletia indica is considered to be a pest that is present in portions of Arizona, not widely distributed and under official control in the United States.

Posted Date: Feb. 27, 2024, 4:12 p.m.