REGULATORY SERVICES

Karnal Bunt of Wheat

Karnal or partial bunt, a plant disease that infects wheat, is caused by the fungus, Tilletia indica Mitra (syn. Neovassia indica (Mitra) Mundk.), which was described in 1931 from the village of Karnal, India. Prior to the detection in Arizona in late February 1996, the disease was known in North America only from Mexico. On March 8, 1996, officials at the United States Department of Agriculture in conjunction with Arizona Department of Agriculture (ADA) announced the detection of T. indica in durum wheat seed that had been inspected during routine sampling by ADA inspectors. On March 21, Agriculture Secretary Dan Glickman announced an aggressive program to deal with Karnal bunt, and included strategies to eradicate the disease and prevent the spread into other wheat-producing areas. Five days later, USDA officials quarantined the entire state of Arizona, four counties in the State of New Mexico, and two counties in Texas. Subsequently, two counties in the State of California have been added to the federal quarantine. Karnal bunt is a national issue; USDA is the lead agency.

Virginia is in a unique position because there are growers and millers, each with different priorities and approaches to wheat diseases. Growers need assurances that Karnal bunt will be kept out of the Commonwealth, whereas millers need assurances that an uninterrupted supply of wheat is able to be shipped to the mills, even if from quarantined areas. Toward both goals, VDACS personnel in cooperation with USDA Animal and Plant Health Inspection Service officials conduct surveys on alternating years from every county in the United States that produces 1 million or more bushels of wheat.

Since October, 1996, there have been multiple incidences of positive detections in several southeastern states including Georgia, Tennessee and Alabama. Virginia is still considered Karnal Bunt free. USDA and respective state officials have developed strategies to deal with any new developments.

For additional information on wheat production and diseases of wheat or on Karnal bunt, follow these links:
Integrated Disease Management in Small Grains