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United States Department of Agriculture

Agricultural Research Service


item Tamez-guerra, Patricia
item Mcguire, Michael
item Medrano-rold Eln, Hiram
item Galen-wong, Luis
item Tamez-guerra, Reyes
item Vega, Fernando
item Shasha, Baruch

Submitted to: Entomology International Congress
Publication Type: Abstract Only
Publication Acceptance Date: 8/31/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Formulation research with Bacillus thuringiensis (Bt) has focused on inclusion of natural products (cornstarch, flour, etc.) as additives to spray tanks or as granular preparations. In the present work, we used a spray dry technique to microencapsulate Bt. The matrices for microcapsules were cornstarch and nixtamalized corn flour (used in Mexico for making tortillas). In addition, the microcapsules contained phagostimulants and solar protectants. The microcapsules were tested in bioassays with lepidopteran larvae of Ostrinia nubilalis on cotton plants, and Heliothis virescens, Helicoverpa zea, Spodoptera exigua, and Trichoplusia ni by incorporation in artificial diets. Microcapsules were produced using: several starch types and wheat flour; variable percentages of A. I.; three antioxidant agents; and solar protectants or negative controls. Toxic activity was compared before and after the spray dry process. Moisture content in each microcapsule was measured as an indication of shelf-life for commercialization. An economic feasibility study compared this product with similar commercial products. The results obtained demonstrate: (i) it is possible to microencapsulate Bt using spray dry technique, (ii) at 3% of A. I. the highest stability and toxic activity of Bt is obtained, (iii) the A. I. can be used at a percentage of 50% without loss of activity, (iv) the materials used are stable and safe, (v) the product is 35% more inexpensive than the actual market products.

Last Modified: 06/22/2017
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