PROGRESS IN THE USE OF CONTROLLED ATMOSPHERES IN ACTUAL FIELD SITUATIONS IN THE UNITED STATES
EDWARD JAY AND ROBERT D'ORAZIO
Stored-Product insects Research and Development Laboratory
USDA, Agricultural Research Service SAVANNAH, GA 31403 U.S.A.
And
Airco Industrial Gases HOUSTON, TEXAS 77055 U.S.A.
ABSTRACT
Field research on the use of carbon dioxide (CO2 for stored product insect control in the United States in the last 3 years is described. Minor efforts were made in sealing the storage structures studied and in 7 tests in upright concrete silos or welded steel bins containing wheat, maize, rice or sorghum the amount of CO2, used/1,000 metric tonnes (t) grain ranged from 3.1 to 4.5 t. However, treatment costs/t of grain ranged from 0.23 to 0.39 U.S. $ because of the availability and low costs associated with CO2 marketing in this country, Additional studies on the use of CO2 in farm storage situations and in rail hopper cars containing flour are also described. The future of the use of controlled atmospheres (CA) in the U.S. is discussed.
INTRODUCTION
Since the last meeting in Rome (Shejbal, 1980) on the subject of controlled atmospheres (CA) there has been an increased interest on the use of this residue-free insect-control technique for pests of grain and oilseeds in storage in the United States (U.S.). This interest cannot be described as an all-out conversion from the use of conventional fumigants to the use of CA. Rather, it can be considered as an inquiry by large grain and oilseed handlers into the effectiveness of the technique with particular emphasis being placed on the economics of the treatment when compared to the costs of using conventional fumigants. This interest is possibly also motivated by the realization that the U.S. Environmental Protection Agency (EPA) may prohibit the use of liquid fumigants containing carbon tetrachloride and methyl bromide for grain treatment in the future in the U.S. This would leave the grain industry with only hydrogen phosphide (PH3) produced by aluminum or magnesium phosphide formulations for the fumigation of grain or oilseeds in post-harvest situations and with CA for treatment of these commodities.