For those still using methyl bromide, it is important to begin researching and trying alternative fumigation methods. Here is a review of some options for structural and commodity fumigations. (Note: Costs are in U.S. dollars.)
Eco2Fume is a mixture of 98% carbon dioxide and 2% phosphine in a cylinder. This fumigant offers safety and efficiency advantages over conventional phosphine. (Eco2Fume: $2.06 -$5.16/1000 cubic feet; methyl bromide: $4.34 -$13/1000 cubic feet.)
Sulfuryl fluoride — to be called Profume if the postharvest version is registered — is already used for wood-destroying pests, but Dow AgroSciences is currently working to register this material for food uses. EPA registration is expected by 2003. Research has shown that the ozone-friendly material is very effective against postharvest insects. The price is undetermined.
This is an effective and fast treatment for flour mills and food processing facilities. Quaker Oats, Ralston Purina, General Mills and Pillsbury currently use heat to treat about 10% of the flour mills and food factories in the U.S. (Heat: $14/1000 cubic feet; methyl bromide: $4.34 -$13/1000 cubic feet.)
Purdue University, West Lafayette, Indiana, U.S., has shown that grain chilling in silos is a potential alternative to methyl bromide. Cold can also be used to treat organic food. This method takes longer and is more expensive than methyl bromide because temperatures must be held cool for a month. (Cold: $1,200/1000 cubic feet per month; methyl bromide: $4.34 -$13/1000 cubic feet.)
Replacing oxygen with carbon dioxide or nitrogen is an effective way to control stored product insects. This technique is often combined with heat, cold or pressure to increase efficacy and decrease the time necessary for control; treatment time can be reduced two to three hours. Cost is variable, depending on what gas is used. (CA: $25/1000 cubic feet; methyl bromide: $4.34 -$13/1000 cubic feet.)
Phosphine is a common fumigant for grain and can be very effective. It can be combined with recycled carbon dioxide and heat to lower the amount needed and increase effectiveness. It is available in tablets, pellets or in gas form. (Phosphine: $2.54-7.62/1000 cubic feet; methyl bromide: $4.34 -$13/1000 cubic feet.)
Inert dusts (diatomaceous earth)
Diatomaceous earth (DE) absorbs the wax coatings on insects so insects cannot retain moisture, causing death by dehydration. It is used primarily as a spot treatment or specific area treatment. (DE: $11.60 – $116/1000 cubic feet; methyl bromide: $4.34 -$13/1000 cubic feet.)
Integrated pest management (IPM) uses a variety of methods to manage pests in a facility. Includes assessment, regular inspections, monitoring, good sanitation practices, maintenance and routine facility observations. Begin by developing an IPM strategy.
Potential options still in research stage:
Propylene oxide, carbon disulfide, carbonyl sulfide and ethylene oxide.
Most of the problems associated with flour milling infestations can be directly attributed to contaminated wheat, according to David Mueller, a U.S. fumigation expert. "Better fumigation of incoming grain can prevent many of the infestations that give rise to needed space fumigation," he said. "In addition, simple sanitation in the mill — cleaning up flour dust and spilled grain — is critical to insure that pests do not have the necessary sites and resources to generate an infestation."