Introduced to the technical aspects of forestry aerial spraying in the
mid-1970's, we were immediately impressed by the complexity of the
process of delivering pesticide to foliage. At that time, there was a
vigorous public debate in New Brunswick about the ecological and public
h alth impacts of the annual spray program for the control of
defoliation of spruce and fir trees by the spruce budworm. The forest
industry is important to the province and changes to the established
procedures of budworm control could have major economic implications. A
rational debate required reliable information about the mechanics of the
spraying process. There was a need to supply missing information as to
required pesticide application rates, atomizer performance, off-target
drift and deposit, and the effects of weather and aircraft operating
factors. We were invited to initiate a research program in this domain
by New Brunswick forest management officials, and what follows in this
book is a logical and quantitative description of the overall process
based on our own research and that of others over the intervening years.
After a short introduction to aerial spraying, we begin (Chapter 2) by
describing forest stands in terms of their interaction with suspended
atmospheric particulate material carried along by the wind and
susceptible to deposition on foliage. We introduce foliage simulators
and their use in measuring the deposit of sprayed pesticide on foliage,
the "biological interface" between pest and pesticide.