Message-ID: <davel.243.0019AA9E@azstarnet.com> Date: Wed, 25 Sep 1996 18:31:42 LOCAL From: David Leonard <mailto:davel@AZSTARNET.COM> Subject: Re: grain storage in sand To: Multiple recipients of list DEVEL-L <mailto:DEVEL-L@AMERICAN.EDU>
In article <mailto:199609251841.NAA02243@mercury.forestry.umn.edu> "Rolfe A. Leary" mailto:<rleary@FORESTRY.UMN.EDU> writes:
>I've read a couple of places that in Africa they store shelled/threshed grain
in >sand to protect it from insects. I have the following questions of someone
>having first hand experience -- just observing is OK too! -- with this method:
>1) on what grains is it applied?
>2) why does this "work"?
>3) what is the ratio of sand to grain?
>4) is a special kind of special sand used, or just "regular" stuff?
>5) is the sand sieved for sizing depending on the grain?
>6) have there been scientific studies to evaluate its effectiveness?
>7) how widespead is the practice?
Rolfe,
Sand and ash are sometimes used for stored-grain insect control and probably work at least 2 ways: 1) Sand scratches the weevil's shell, making it more prone to dehydration.; 2) Sand and ash both fill up pore spaces, hampering insect movement.
One reference recommends a 10 liter bucket of fine sand per 100 kg of grain. In Jamaica, wood ash or slaked lime (calcium hydroxide) at 3 parts per 1000 gave OK results on cowpeas.
Vegetable oil is a more effective method and works with maize, cowpeas, beans and (probably) grain sorghum. It plugs up the weevil's pores... Peanut, coconut, palm oils and probably any other vegetable oil at 5-10 cc per kg of grain (evenly mixed) are effective. Reinfestation often occurs within 60 days. The treatment doesn't affect taste or appearance.
Some references:
SMALL FARM GRAIN STORAGE HANDBOOK, Peace Corps, Washington
NATURAL CROP PROTECTION, Gaby Stoll, AGRECOL, Josef Margraf Publisher, 1987
ECHO DEVELOPMENT NOTES, Issues 14 (March '86) and 15 (June '86)
Regards
David Leonard Consultant in hillside-farming systems and agro-nutrition