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Tyroglyphid mites in stored products Methods for the study of population density
Author(s) -
Solomon M. E.
Publication year - 1945
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1945.tb06762.x
Subject(s) - biology , population , dust mites , population density , funnel , sampling (signal processing) , materials science , environmental science , computer science , environmental engineering , allergy , demography , sociology , allergen , immunology , filter (signal processing) , computer vision
The known methods for detecting the presence of tyroglyphids are described. For coarse materials, such as seeds, sieving is recommended. For flour, it is better to examine exposed surfaces, or to keep samples in glass vessels and examine for the runnels made by mites against the glass. Methods of sampling to provide information about the density and extent of infestations are described. Samples must usually be treated in the laboratory. While methods which do not involve the separation of the mites from the material are referred to, such separation is usually necessary. Mites may be separated from most materials by the modified Berlese funnel method of Chernuishev and Petrova; means of overcoming certain disadvantages are suggested. However, vigorous sieving is recommended for coarse materials, and a flotation method, using dichlorethylene, for fine materials such as flour. It is usually more satisfactory to examine and count the mites than to estimate the numbers volumetrically or gravimetrically. They are counted in a dish containing oil, placed on squared paper under a low‐power microscope. A modification of this method, for dealing with large numbers, is described. Methods of expressing population density are briefly discussed.