Phytosphere Research - Horticulture / Urban Forestry / Plant Resources / Agriculture

California Oak Disease and Arthropod (CODA) host index database  

NEW! A web-based version of CODA

We have been seeking to make the data in CODA available through a web-searchable database for some time. Currently, USDA-Forest Service Region 5 has provided some funding for this project. Phytosphere Research is working cooperatively with Forest Service staff to develop this resource. As part of this project, we will be adding images of agents and symptoms to CODA. We are actively seeking good-quality images of oak disease and pest symptoms and that can be used in the web version of CODA. Please contact Phytosphere Research if you have images that you would be willing to contribute to the digital image collection or if you would like further information about the web-based version.


Our goal in creating The California Oak Disease and Arthropod (CODA) host index database and program was to increase communication and understanding about oak pests and diseases in California, in order to help protect and enhance our state's valuable oak resources. New and updated information is added to the database as it is received, so the CODA database can serve as a clearinghouse for information on diseases and pests of California oaks.

The CODA database and its access program were originally developed for the Forest and Rangeland Resource Assessment Program (now FRAP) of the California Department of Forestry and Fire Protection (CDF). Ongoing maintenance and distribution of CODA is provided as a public service by Phytosphere Research. The database was developed by Ted Swiecki and Elizabeth Bernhardt (Phytosphere Research), Richard Arnold (Entomological Consulting Services, Ltd.), and Jim Kellogg (Tierra Data Systems). 


The CODA host index database and program is a comprehensive computerized compilation of the many agents that affect oaks in California. CODA currently contains records for more than 1800 arthropods (insects and mites) that feed directly on oak tissues. CODA also documents more than 750 interactions between oaks and microorganisms. The microorganisms in CODA include plant pathogens, saprophytes, and mycorrhizal species. The information in CODA comes from over 300 published and unpublished sources.

CODA contains specific information for each reported host-agent interaction, including the fields that describe the following:

--reported distribution of the host-agent interaction
--types of growing situations (e.g., range, urban landscape) under which the interaction has been observed
--host life stages attacked
--host symptoms and agent signs, including the location and maturity of affected plant parts
--whether the agent attacks healthy or compromised tissue
--whether symptoms listed are a direct or indirect result of attack
--other notes about the interaction

Because of the limitations of available data, many records in CODA do not contain complete information in all of these fields.

CODA also contains information specific to each disease agent, host, and reference. Disease agents and arthropods are identified with hierarchical taxonomic and non-taxonomic codes. True taxonomic synonyms as well as other scientific names that have been encountered in the literature are listed in a synonym field for each agent. CODA also contains descriptions of the included oak host species, and full literature citations and descriptive notes for references.

The information in CODA is found in a set of related DBase III-compatible database files. The simplest way for most users to access the data is via the CODA access software, which can be downloaded from this site.

Read our online paper on CODA for further statistics and information on arthropod pests and diseases of California oaks.


The CODA access program is a DOS application designed specifically to access, filter, and produce reports on information in the CODA database. The program includes functions to translate all coded information on screen and in printed reports. A filter function allows the database to be searched for specific agent-host combinations that match various user-supplied criteria, such as specific symptoms. This enables the user to generate lists of agents that might be the cause of a certain type of damage, for example. The report function includes the option to send the report to a file, which can subsequently be edited and formatted with a word processing program.

The access program will run on most PCs that can run MS-DOS applications, including PCs running Windows 3.1, 95/98, NT and Apple Macintosh computers with software that emulates DOS. In order to run the CODA access software, you need at least 5 megabytes of hard disk free space, and DOS version 3.3 or higher. However, the access program is incompatible with some network drivers and some glitches show up on newer operating systems.   The current version of the access program is version 3.3, released in July 1993, so it is in many ways a fossil. 

CODA was previously distributed by mail, but is now available only through download from this site. You should also download a copy of the User Manual, which describes how to load and use the CODA access program.

  • Download the User Manual (Released 10/00, ASCII text file, 58K)
  • Download the CODA access program (Version 3.3, self-extracting PKZIP compressed file, 138K)


    The most current CODA database files are at the web based version of CODA. An old version of the CODA database files are available for downloading at this site. The files are compressed in a self-extracting file named CODAnnnn.EXE where nnnn are four digits corresponding to the data release month and year (e.g., CODA0697.EXE is data release 6/97).
  • Download CODA database files (Release 11/00, self-extracting PKZIP compressed file, 367K)
  • The current database files available for downloading from this site were last updated in November 2000.


    If you have a copy of the CODA access program version 3.3 installed on your computer, you can update the data files using the following procedure:
    1. Copy the CODAnnnn.EXE file to the directory that contains the CODA software (usually C:\CODA).
    2. From a DOS prompt within the CODA directory, type the name of the CODAnnnn.EXE file. Alternatively, from the Windows (3.1) File Manager, you may simply double click on the filename. If you use File Manager, be sure to press F5 (or click Window/Refresh) so that the newly expanded files will show up. The files UPDATE.BAT and CODAFILE.EXE should now be in the CODA directory.
    3. From a DOS prompt within the CODA directory, type UPDATE. If using the Windows (3.1) File Manager instead, you may simply double click on the file UPDATE.BAT. The update program will erase the old database index files, decompress the new database files and overwrite the old ones, and finally erase the CODAFILE.EXE and UPDATE.BAT files.
    4. Note: You may need to manually expand the files in the file if the self-extraction program fails on your system. Open the directory in Windows explorer and double click on the file. Most systems have utilities that expand .zip files. If yours doesn't, you can get a free download of PKZIP from PKware (
    5. You can now start the CODA program in the usual way. There will be a delay as the index files are recreated the first time you use the program after updating.
    6. Once you are satisfied that the update was successful, you may want to erase the CODAnnnn.EXE file.
    PLEASE NOTE: The CODAnnnn.EXE file contains only the data files used by the CODA access program. You must have the CODA version 3.3 access program to run the CODA program, so don't erase all the old files in the CODA directory!!


    If you have questions about the CODA program, or additional information that should be included in CODA (new records, taxonomic changes, additional range or symptom information, etc.) please contact: Return to Phytosphere Research Home Page

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