EPPO Global Database

EPPO Reporting Service no. 04 - 1996 Num. article: 1996/62

Tilletia indica in United States

We publish here the NAPPO report concerning the first record of Tilletia indica (EPPO A1 quarantine pest) in United States.

'The U.S. Department of Agriculture in conjunction with the Arizona Department of Agriculture, announced on March 8, 1996, that Karnal bunt, a fungal disease of grain, was detected in durum wheat seed in the State of Arizona. Suspect seed samples were detected at a seed dealership during routine testing by the Arizona Department of Agriculture. After forwarding samples to the State's agricultural lab, USDA's Agricultural Research Service was given samples for final confirmation. The disease was confirmed as Karnal bunt on March 8, 1996.

Karnal bunt, or partial bunt, is a fungal disease of wheat, durum wheat, and triticale, a hybrid of wheat and rye. Infected plants produce less grain, and the quality of the grain itself is lessened. Typically, only a portion of the kernel is affected, which is why the disease is sometimes called partial bunt. The disease is caused by the smut fungus (Tilletia indica Mitra (also known as Neovossia indica) and is spread by spores. It has been reported in India, Pakistan, Afghanistan, Iraq, Brazil and Mexico. This is the first report from the United States.

Following the detection of Karnal bunt in Arizona, a scientific panel comprised of State, Federal and industry technical experts was convened to determine further actions. Investigators are tracing the source and distribution of all confirmed Karnal bunt positive seed while officers of USDA's Animal and Plant Health Inspection Service and State regulators impose the appropriate regulatory actions to prevent the further spread of Karnal bunt. A statewide survey of all Arizona wheat varieties continues.

As of March 20, 1996, Karnal bunt has been confirmed in four varieties of durum wheat: Reva, Durex, Ocotillo and Kronos, in Arizona. Two samples of wheat which originated in Arizona and were submitted to New Mexico's State Agriculture laboratory were also confirmed positive for Karnal bunt. One sample is from Durex variety seed that originated in Arizona and has been planted near Fabens, Texas. The second sample is from Durex variety seed that originated in Arizona and has been planted near Demming, New Mexico.

According to USDA's Economic Research Service's Wheat Yearbook, durum wheat is expected to account for 4.7 percent of the total wheat produced in the United States in fiscal year 1995-96.

Emergency quarantines have been issued to restrict the movement of seed, machinery, and soil from farms where the infected seed has been planted. State and Federal quarantines will be placed to augment this emergency action. In accordance with the International Plant Protection Convention, trading partners are being informed of the detection through the Food and Agriculture Organization (FAO) of the United Nations and NAPPO. A wheat export certification team has been established by APHIS/PPQ to develop options for dealing with potential trade issues. For further information, contact the Phytosanitary Issue Management Team, PPQ/APHIS, Riverdale, Maryland, telephone (301) 734-5261, and fax (301) 734-7639.'


NAPPO Newsletter, 16 (2), in press.