University of California Cooperative Extension is surveying for rice diseases this fall. The objective is to document the incidence of diseases in Sacramento Valley rice fields to justify to the California Air Resources Board the industry needs to continue burning 25% of its acreage annually.
Every five years, the air board has to reapprove the straw burning program. One reason for letting growers burn their fields is disease control so it is important to collect data on the presence of diseases.
The straw burning program is the result of the Connelly-Areias-Chandler Rice Straw Burning Reduction Act of 1991, which phased out open-field burning of rice straw as of 2000. But a provision in the legislation allowed for burning of up to 25% of a grower’s fields each year if disease was documented.
Any burning also is subject to the grower obtaining the necessary permits from the local air quality management district.
A crew of four to five UC representatives will stop in random fields in the major rice producing counties to inspect for the presence of diseases in 30 sites in each field.
They will look for stem rot, aggregate sheath spot, kernel smut and blast. The precise location of each field won’t be disclosed, only the general location and county.
So far, the crew has inspected 10 fields in Butte County and has found very low levels of blast and kernel smut. Stem rot and aggregate sheath spot are more variable; they have found fields with very little of these diseases and fields with a lot.
University of California Cooperative Extension contributed information for this article.