University of California

Chemical seed treatment for the control of seedling disease of water-sown rice


R. K. Webster
D. H. Hall
J. Bolstad
C. M. Wick
D. M. Brandon
R. Baskett
J. M. Williams

Authors Affiliations

R. K. Webster was Associate Professor of Plant Pathology and Associate Plant Pathologist in the Experiment Station; D. H. Hall was Extension Plant Pathologist, California; J. Bolstad was Staff Research Associate-all at Davis, California; C. M. Wick was Farm Advisor, Butte County; D. M. Brandon was Farm Advisor, Colusa, Glenn, and Yolo counties; R. Baskett was Farm Advisor, San Joaquin County; J. M. Williams was Farm Advisor, Sutter-Sacramento counties.

Publication Information

Hilgardia 41(21):689-698. DOI:10.3733/hilg.v41n21p689. May 1973.

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The most effective fungicide formulations, rates, and method of application for reducing seed rot and seedling disease of water-sown rice were determined in greenhouse and field studies. The efficacy of over 30 chemical formulations that had shown biological activity against Achlya klebsiana and Pythium sp. in laboratory and greenhouse trials were tested. Difolatan® and captan treatments have consistently been the most effective in improving total stand establishment. Treatment by either slurry or spray mist with flowable formulations and allowing the fungicide to dry on the seed prior to the soaking process proved to be more effective in preventing seed rot and seedling disease than application made after soaking or by adding the chemicals to the soak water. Seed treated prior to soaking showed no detrimental effects from the chemicals after storage up to four months. Analysis of chemically treated seed before and after soaking and of the soak water revealed that substantial portions of the fungicide were lost during the soaking process. The benefits from fungicide seed treatment in water-sown rice are most obvious during the early planting season, when environmental conditions are often unfavorable for germination and seedling growth.

Literature Cited

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Finfrock Dwight. Seed treatments for rice. 1957. Davis, California: Agronomy Dept. Circular. Univ. of California. (Limited distribution).

Lamey H. A. A technique for laboratory evaluation of seed treatments to control rice seed rot. Plant Dis. Reporter. 1965. 49:736-38.

Mikkelsen D. S., Sinah M. N. Germination inhibition of Oryza sativa and control by preplanting soaking treatments. Crop Sci. 1961. 1:332-35. DOI: 10.2135/cropsci1961.0011183X000100050010x [CrossRef]

Webster R. K., Hall D. H., Heeres Jacob, Wick C. M., Brandon D. M. Achlya klebsiana and Pythium species as primary causes of seed rot and seedling disease of rice in California. Phytopathology. 1970a. 60:964-68. DOI: 10.1094/Phyto-60-964 [CrossRef]

Webster R. K., Hall D. H., Wick C. M., Brandon D. M. Seedling disease and its control in California rice fields. The Rice Journal. 1970b. 73(8):

Webster R, Hall D, Bolstad J, Wick C, Brandon D, Baskett R, Williams J. 1973. Chemical seed treatment for the control of seedling disease of water-sown rice. Hilgardia 41(21):689-698. DOI:10.3733/hilg.v41n21p689
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