File:Annual report (1954) (18424885662).jpg

Title: Annual report
Identifier: annualreport19541958ento (find matches)
Year: 1872 (1870s)
Authors: Entomological Society of Ontario; Ontario. Dept. of Agriculture
Subjects: Entomological Society of Ontario; Insect pests; Insects
Publisher: Toronto, The Society
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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70 REPORT OF THE ENTOMOLOGICAL Sorption of the fumigant by the commodity and the jute bags containing it is considerable. That the peanuts themselves, and not the jute bags, are mainly responsible for the retention of fumigant is demonstrated by the results of a separate test on three empty bags, shown in Table I. The thermal conductivity gas anlyser used in this work withdraws the gas air mixture at the rate of one cubic foot per hour, which is approximately equal to 0.5 litres per minute. In order to make an accurate reading at any point it was usually necessary in the laboratory tests to run a given sample for two minutes. Thus for analysis at a given point one litre of the fumigation atmosphere passed through the machine. In a small chamber of the size used in the laboratory there is obviously only an approximation in the determination at anv one point unless equilibrium has been attained throughout the system. In the present study the gas analyser was used in the laboratory because a direct com- parison was being made with the results from the use of the instrument in the field.
Text Appearing After Image:
Fig. 3. Methyl bromide concentrations during fumigation of b"'>s of shelled peanuts in laboratory chamber and in railway freight car. "E" indicates readings in empty chamber. The circled numerals refer to sampling points, Avhich are described in the text. Ship Fumigation The results of the fumigant anlysis made during the treatment on board the ship are compared in Fig. 2 with a fumigation in the laboratory of approximately the same weight of material per volume of space. Temperature conditions in the commodity were identical in both treatments. The use of circulating fans throughout the cargo space of the ships led fairly rapidly to the attainment of a state of equilibrium throughout the system. The continued slight fall in concenration up to the end of the treatment is in agreement with observations made in the laboratory chamber. This may be attributed, therefore, to the effect of sorption of the fumigant by the load, which is a continuous process for the times observed in this study.

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