Products and over 400 private landowners to spray 76,000 acres of infested
timberland. The Bennett Lumber millsite served as helibase for the project, with
Heli-Jet contracted to do the flying. Each helicopter was equipped with a
sophisticated GPS guidance system. Spray boundaries were programmed into the
GPS unit each day and, with twenty-four satellites guiding the helicopters, they flew
precise patterns over areas of caterpillar infestation. Each helicopter's GPS unit was
fitted with a memory card which stored the day's spray activity. When the spraying
was done, records of the day's flight data were downloaded into Bennett Lumber's
computers where precise maps of spray area coverage were generated using a
geographical information systems (GIS) program called ArcView.
Two insecticides were used as spray for the Tussock Moth - Dimilin and 'Bt'. Dimilin
is an insect growth regulator. It prevents the skeleton from forming and without a
skeleton the caterpillars structure cannot hold together and they die. 'Bt', or Foray,
is a microbial insecticide and a naturally-occuring bacterium commonly found on
foliage and in the soil. It paralyzes the digestive system after the caterpillar
consumes it.
After many hours of preperation and hard work, the project was successfully
completed and proved to be over 90% effective. It is possible, however, for the
remaining moths to re-invade forest stands up to a quarter mile or more. It may be
advisable for landowners to spray high value trees being attacked or around homes
for visual and health reasons.
If you have any questions, please contact the Idaho Department of Lands Forest Practices Advisor at (208) 877-1121. Click here for more info on the Tussock Moth.
