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United States Department of Agriculture

Agricultural Research Service


item Connick Jr, William
item Daigle, Donald
item Pepperman Jr, Armand
item Hebbar, K
item Lumsden, Robert
item Anderson, T
item Sands, D

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: It may be possible to control undesirable vegetation with fungi that can attack the plants. These naturally-occurring fungi are safe for humans and the environment. We have put these fungi into granules in a concentrated form that is stable and easy to apply. We learned how to increase production of granules from laboratory-scale to the pilot plant. The lessons learned can be applied to similar products for weed and insect control using harmless microorganisms instead of chemical pesticides.

Technical Abstract: Biomass of formae speciales of Fusarium oxysporum pathogenic to the narcotic plants coca (Erythroxylum coca) and opium poppy (Papaver somniferum) was incorporated into wheat flour-kaolin granules (Pesta). Shelf life (inoculum viability) of samples with the coca pathogen (strain EN4-S; 2.6 X 10(7) colony-forming units (cfu)/g, mostly chlamydospores) was at least one year at 35C when stored at a water activity (a(-w)) of 0.12 (12% relative humidity) and two years when stored at 25C. Shelf life of samples with the poppy pathogen (strain CP3A; 3.4 x 10(7) cfu/g, mostly microconidia) was slightly less than that of samples with the coca strain EN4-S. By optimizing water activity (near 0.12 for F. Oxysporum) and incorporating at least 5 X 10(6) cfu/g of chlamydospore inoculum, an exceptionally long shelf life was obtained for a product containing a living biocontrol agent. Process scale-up to multi-kilogram quantities was accomplished using twin-screw extrusion and fluid bed drying.

Last Modified: 10/19/2017
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