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RELATIONSHIP BETWEEN MICROBIAL NUMBERS AND DROPLET SIZE IN AERIAL SPRAY APPLICATIONS

Published online by Cambridge University Press:  31 May 2012

O. N. Morris
O. N. Morris
Affiliation:
Chemical Control Research Institute, Environment Canada, Ottawa, Ontario K1A 0W3
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Abstract

Experiments were designed to determine the actual number of spores and crystals of Bacillus thuringiensis (B.t.) and of nuclear polyhedral virus and entomopoxvirus deposited at ground level per unit area and to determine any change in spore:crystal ration following aerial application in forested plots.

The results indicate that: (1) The estimation of B.t. aerial spray deposits by the commonly used agar plate method grossly underestimates the deposit rates of active ingredient. The tracer dye method more accurately estimates deposit rates for both B.t. and entomopathogenic viruses. As a dye 0.1% Erio Acid Red XB is recommended. (2) The relationship between drop size and the number of spores and crystals or virus inclusion bodies/drop is curvilinear. This relationship probably holds true regardless of spray volume rate. All visible spray deposits at ground level contained some active ingredient. (3) With B.t. sprays the sporexrystal ratio emitted from the aircraft is not changed upon target impact.

Type
Articles
Information
The Canadian Entomologist , Volume 109 , Issue 10 , October 1977 , pp. 1319 - 1323
Copyright
Copyright © Entomological Society of Canada 1977

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