Fumigation trials with carbon disulphide:carbon tetrachloride (20:80) in silo bins.
Trials were carried out in Shanghai, China, to develop a simple fumigation system for grain stored in silo bins. Preliminary experiments in the laboratory and on a pilot scale showed that a mixture of carbon disulfide with carbon tetrachloride at 20:80 w/w was an effective fumigant against Sitophilus zeamais, Tribolium castaneum and Cryptolestes pusillus at a rate of 331 g/m3 for a 7-day exposure period at about 29°C grain temperature. A dosage of 220 g/m3 gave incomplete control. It was found that the fumigant mixture applied to the grain surface in 2 sealed test bins 30 m high at 331 g/m3 gave complete control of test insects (including immature stages of T. castaneum and pupae of S. zeamais) placed in the grain close to the surface. Both fumigant components penetrated the grain mass rapidly and were retained at substantial concentrations for more than 10 days.