ODC (tm): Is This "Stuff" for Real and How Does It Work?

Originally posted 4.12.10, this post is from the Kansas State University Department of Entomology Newsletter, March 26, 2010 authored by Raymond A. Cloyd, Professor and Extension Specialist in Ornamental Entomology/Integrated Pest Management.  Dr. Cloyd is affiliated with the Department of Entomology at KSU in Manhattan, KS.

The entire publication can be found at http://www.entomology.ksu.edu/DesktopDefault.aspx?tabid=756, look for issue #1, March 26, 2010. 

"We have received numerous inquiries regarding the product Organic Disease Control or ODC (tm), and its supposed effectiveness against insects and diseases.  This product contains chitosan (0.25%) as the active ingredient and is being marketed by AgriHouse, Inc., (Berthoud, CO) with claims that the product protects trees from attack by pine beetles and blue stain mold.  First of all, it is important to discuss the characteristics of the active ingredient.  Chitosan (poly-D-glucosamine) is a common polymer present in nature in the cell walls of certain fungi and insects, and the commercial formulation is prepared from chitin that is found in the shells of crustaceans (e.g., crabs and shrimps). Chitosan is supposed to enhance, stimulate, or boost the plants immune (or defense) response.  Well, how does it do this?  It has been proposed that chitosan is active on the octadecanoid pathway.  What happens in this pathway is that linolenic acid is converted to jasmonic acid resulting in the transcriptional activation of genes associated with defense that "turns on" compounds and/or enzymes  such as proteinase inhibitors and polyphenol oxidase.  In other words, chitosan may elicit or activate plant defense responses.  However, the mechanisms affiliated with this process are not clearly understood.   

Currently, there is no quantitative information (based on scientific studies) on the efficacy of ODC (tm) against the mountain pine beetle (Dendroctonus ponderosae) in lodgepole or ponderosa pine.  Furthermore, the publications (#672 and #5322) referred to in the in-house blog (http://agrihouse.wordpress.com/) do not contain any conclusive data to substantiate the claims being made associated with this product.  In fact, one of the publications presented only one years' worth of data (1996) and did not even test for activity against bark beetles.  Additionally, the methodology or procedures used (inoculation) are questionable.  I have listed four publications at the end of this article that discuss the potential role of chitosan; however, none of these are studies that have conducted or include evaluations against wood-boring beetles."

Dr. Cloyd goes on to talk about the claims made regarding ODC (tm) and his questions to each of the claims.  If you are interested in reading the rest of the article, I encourage you to click on the KSU link above to access the full story.  The bottom line, according to Dr. Cloyd, is that "overall, this appears to be an example of an 'aggressive marketing' strategy, which may cause confusion among homeowners/consumers.  As such, this supports the value of extension at land-grant universities because it is our responsibility as extension personnel to provide un-biased information to homeowners/consumers so they can make sound pest management decisions based on the results from 'sound' science.....not mis-information."