[Digestion] Pest repellent capability of biogas slurry - information request

Anand Karve adkarve at gmail.com
Tue Dec 23 06:43:29 MST 2014

Dear List,

I too had been thinking about the insect repellant activity of the
effluent from a biogas plant and I feel that I should share my
thoughts with this group.  The food of all animals, whether they are
insects, cephalopods, mollusks, or vertebrates, consists of sugars,
starch, cellulose, proteins and fats. It should be noted that
molecules of all these substances contain oxygen.  My experience so
far has been that any organic feedstock, which is introduced into a
biogas plant must contain oxygen as a part of its make up. This is
because the methanogens as well as other anaerobic microbes obtain
their oxygen from their food. Modern animals can obtain molecular
oxygen from the air or from that dissolved in water, but since they
evolved from the Archaea, they seem to have retained the
characteristic of eating only such organic matter, which contains
oxygen. No animal can digest organic substances without oxygen. Since
the organic matter coming out of a biogas plant is devoid of oxygen,
it is obvious that insects are not attracted to it.
Dr. A.D. Karve

Chairman, Samuchit Enviro Tech Pvt Ltd (www.samuchit.com)

Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)

On Tue, Dec 23, 2014 at 4:00 AM, Hoysall Chanakya
<chanakya at astra.iisc.ernet.in> wrote:
> Dear Digestion list members
> Merry Christmas and a Happy new year
> I will attempt to examine the pest repellent properties of digester liquid
> from an anaerobic digester and I request list members if they could share
> any such experience- documented, published or simply visually
> authenticated on this subject.
> I am inspired by the fact that between 1992 and 2006 organic farmers of
> the Low external inputs and sustainable agriculture (LEISA) network in
> South India fermented leaves of local weeds and sprayed the filtered
> digestate (25d old) to obtain pest repellent action for periods between
> 3-7d for many sucking pests (aphids and jassids), red hairy caterpillar
> (groundnut), pink boll worm (cotton) and many less described pests of
> paddy, green gram and a few vegetable crops.
> Please share with me any such information if you know of any,.  I am
> attempting to document and experiment the same.  The irony has been that
> for long (over 40 years) we recommended that digestion of cattle dung
> because it removes the property of attraction to flies and only very few
> workers have attempted to determine if it actually repelled insects (and
> pests).
> With best wishes
> And thanking you in advance
> Chanakya
> chanakya at astra.iisc.ernet.in
> hoysull at gmail.com
> --
> Center for Sustainable Technologies
> Assoc. Faculty. Center for Contemporary Studies
> Center for Infrastructure, Sustainable Transport and  Urban Planning
> (CiSTUP),
> Indian Institute of Science, Bangalore
> --
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