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United States Department of Agriculture

Agricultural Research Service

Title: Corn Flour As a Matrix Forming Material for Encapsulation of Biological Pesticides

Author
item McGuire, Michael

Submitted to: Corn Dry Milling Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 30, 1996
Publication Date: N/A

Technical Abstract: Gelatinized corn flour offers an ideal substrate for use as encapsulating agent for biological pesticides such as insect active bacteria and viruses. Some of our past research has focused on granular formulations of Bacillus thuringiensis, a bacterial insecticide. In cooperation with Dr. Pat Dowd, we have extended this work to malathion. We have found that significantly less pesticide can be used without loss of plant protection. Once applied, the granules stick to plants and resist wash-off by rainfall or removal by wind. Thus, repeat applications are not necessary. In addition, natural enemies are spared to some extent because the pesticide is not applied as a blanket spray; instead discreet granules contain the poison. Once an insect finds the granule, it feeds and ingests a lethal dose. Previous work in our laboratories has also looked at the use of gelatinized flour as a spray adjuvant. While we have shown the effectiveness of such spray tank additives in response to solar and rain protection, commercialization has been slow for a number of reasons. One of these is the fact that different amounts of flour are necessary based on the spray volume used by the farmer. We have recently found, in cooperation with Mexican scientists, that modified flour can be mixed in a slurry with active and other inert ingredients and dried together to form small sprayable granules. This microencapsulated product still maintains solar stability but rainfastness is lost. The original starting flour was nixtamalized but we have also demonstrated the process with flours and starches more commonly available in the U.S.

Last Modified: 7/31/2014
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