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United States Department of Agriculture

Agricultural Research Service

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Biofilm is a complex aggregation of microorganisms that adhere to a solid surface and excrete a protective and adhesive matrix.  These microbial assemblages have both structural heterogeneity and complex community interaction. 


Microbes form biofilms in all ecosystems; however, the role of biofilm in microbial colonization of plant surfaces and, more importantly, in survival of microbial biological controls applied to plant surfaces is poorly understood.


Our research investigates biofilm formation by a bacterial biological control agent (FP62) of Botrytis cinerea and how this impacts colonization and disease control.  Using our observation that biofilms and polysaccharides are important in successful bacterial biocontrol agents, we developed spray adjuvants that increase the efficacy of commercial biocontrol agents and compost teas. 



The biocontrol agent, FP62 colonizing the surface of a geranium leaf.  The biocontrol is completely covering a glannular trichomb.





Micrographs of geranium leaves one week after inoculation with a microbial suspension with the addition of 0.1% Karaya, a polysaccharide, (A) and  without (B).  Control efficacy of Serenade (AgraQuest, Inc) and effects of the addition of spray adjuvants (C).



Our Mission

Powdery Mildew



Gray Mold

Blackberry Rust




Scientist: Walt Mahaffee



Last Modified: 1/7/2013
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