Diseases
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 Bakanae |
Bakanae was first detected in California in 1999 and has since spread to many rice producing areas in the Sacramento Valley. It is transmitted primarily by seed. Disease levels so far have been quite low and yield loss not measurable. However, disease incidence level and number of fields affected has increased dramatically. UC is working on promising seed treatment materials but research is not sufficiently advanced to make recommendations. However, breeders of seed of public varieties, which is the first generation in producing certified seed, will be treated to maintain a clean seed supply, and will be used in some fields in California in the 2002 season. For more information on bakanae see:
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Rice Blast |
Blast, a fungal disease of rice, was identified in California for the first time in September 1996 and has recurred every year since. However, disease pressure was low from 1998 to 2001 and few fields were treated, although blast continues to be found in new areas every year. Azoxystrobin (Quadris®) was approved for blast control in California beginning with the 1997 season. Field surveillance continues annually to detect blast presence, and research is underway to develop durable resistance in California adapted cultivars. A blast early warning system was implemented by a private company in 2000 to 2001, with partial support from the Rice Research Board and University of California. It combined scouting with a weather station network. One of the goals is to develop a blast predictive model for California conditions. The model relies primarily on leaf wetness and temperature during periods of leaf wetness. When coupled with visual identification of spores that would provide inoculum, the model will potentially assist growers in making informed spray treatment decisions. Information on the importance, symptoms, and control of rice blast have been assembled in the following publications:
Blast is one of three qualifying diseases for purposes of the conditional burn program which began September 1, 2001. The other diseases are stem rot and aggregate sheath spot. To obtain a permit to burn rice straw, rice growers must inspect their fields and determine if they have a "significant and quantifiable disease." For more information see:Rice Disease Certification Program for California, Feb 2002. |
Modified: 29 Aug 2003 |
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