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Most science solutions miss the bottom billion people. Our Bottom Billion Science page is an attempt to provide information to that population of people that needs our help the most. Our current emphasis is on reducing the 20-80% of grain losses to pests after harvest. If we can reduce these losses, hunger could be reduced and food security increased. Unfortunately, this is an area overlooked by too many funding and aid agencies. You can read more on post-harvest losses at www.phlosses.net and world hunger at www.wfp.org/hunger.

Click here to download our Journal paper documenting solutions to reduce losses in developing countries

 

 

 

 

Methods of controlling stored-grain pests:


Spinosad is effective at controlling lesser grain borer after short exposure, but was less effective at controlling rice weevil, red flour beetle, and the psocids (Athanassiou 2010, J. Econ. Ent). Another study showed that the lesser grain borer and larger grain borer were very susceptible to spinosad, followed by rice weevil. The confused flour beetle was least susceptible (Athanassiou et al, 2008, J. Insect Sci.).

Actellic Super, Stocal Super, Shumba Super (all pyrethroids), Protect-It, and Dryacide (diatomaceous earths) each provided protection of uninfested grain for 40 weeks. If grain is infested prior to treatment, the Actellic Super dust was most effective. Actellic must be obtained from an approved source and applied correctly to be effective. Traditional treatments such as cow dung ash, sunflower head ash, mkalya, rice husk ash, wood ash, marimba, or giri giri mo showed little or no improvement over untreated controls (Stathers et al 2008, Crop Protection).


Diatomaceous earth formulations Protect-It, PyriSec, and DEA-P were evaluated for controlling the larger grain borer. DEA-P was the only formulation that was effective (Athanassiou et al, 2007, J. Econ Ent.)


Combining diatomaceous earth with pyrethroids improves control of rice weevil and confused flour beetle, but the pyrethroid alone provided good control (Athanassiou 2006, Crop Protection).


Hermetic (oxygen free) storage can be an effective means of controlling insects. The container must be air-tight, and grain must be dry before storing. We have shown that metal containers, rigid plastic containers, glass jars, and hermetic plastic bags (such as those marketed by GrainPro, www.grainpro.com) can control lesser grain borer in stored grain (Dowell, C.N. and Dowell, F.E. , 2009, unpublished). One key to this method is preventing any source of air leaks, such as damage to bags by rodents. Quezada et al (2006, Postharvest Biology and Technology) showed 100% control of larger grain borer by hermetic storage. Murdock et al. (2003) has shown that triple bagging is effective at controlling insects in some grain. This cheap and effective technique is used in some West Africa countries.


Bednets treated with permethrins such as deltamethrine can provide effective control of lesser grain borers (Dowell, C.N., and Dowell, F.E., 2010, unpublished).

Thus, there are many different ways of controlling pests in stored grain. Local availability and economics will influence the selection of proper insect control methods.

 

Typical stored grain pests:

· Lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

· Rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

· Confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae)

· Larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae)

· Psocid, Lepinotus reticulates (Enderlien) (Psocoptera: Trogiidae).

Types of products used to control insects:

· Spinosad (Dow AgroSciences) is a pyrethroid, labeled for use at 1 ppm in the US.

· Actellic Super (Syngenta), Stocal Super (same product from different vendors, containing 1.6% pirimiphos-methyl and 0.3% permetrin, and Shumba Super (1% fenitrothion and 0.13% deltametrin) are other pyrethroids.

· Diatomacieous earths (DE’s) are naturally occurring insecticides that are non-toxic to mammals. Often applied at 1000 ppm. Commercial products include Protect-It, PyriSec, DEA-P, and Dryacide.

It is essential to store grain at the proper moisture content! This is about 12-15% for maize. The longer the intended storage time and the warmer the temperature, the lower the moisture content must be.