UBC Theses and Dissertations
Crystal forms and availability of lindane residues to an ambrosia beetle Pennell, James Thomas
Some of the factors affecting the form and size of crystals produced by the solvent exchange method are described for lindane. The effect of different crystal forms on the availability of this toxicant to the ambrosia beetle Trypodendron lineatum (Oliv.) was evaluated from gross functional effects. The beetles were brought into contact for known periods of time with deposits of a prescribed dosage of lindane crystals of two forms. Mortality was used as an index of the availability of the different deposits. The loss in weight with time was followed for deposits of different dosages of lindane crystals of the two forms, as a possible factor contributing to differences in residual toxicity. With dosages corresponding to those used for preventing damaging attacks on logs by this ambrosia beetle, viz. 180 mg./ft.² , no difference in effect was demonstrated between crystals of the two forms. No striking difference in rate of residue loss was demonstrated when deposits "aged" in a draught free cupboard. The minimum and maximum temperature recorded in the cupboard during the storage period was 14.5° and 23.5°C. The concept of availability of insecticidal deposits and the factors affecting it are discussed.
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