Aerial spraying of insecticide against Pine Beauty
The photograph is courtesy of the family of George Dey. George took many forestry photographs in his forestry career and many are now shown on this web site. Check under ‘Groups’ and George Dey Collection.
Another view of the spraying action of aircraft as it passes over the forest. The aircraft was guided by triangulation signals from transponders which were set up on very high and distant locations but uncertain of how this was done. The application method was to start spraying across the wind on the down wind side of the attacked zone and continue spraying in strips moving gradually up wind. The aim was to allow the gentle wind to blow the tiny droplets in and around the full canopy of all the affected trees.
In preparation for spraying, water supplies from within affected areas had to be cut off and resupplied by other means, large unsprayed buffer strips had to be left everywhere near houses, rivers and major streams and people were excluded from within the spraying zone. The spraying chemical most often used was ‘dimilin flo’ (diflubenzuron) which stopped the process of the larvae shedding their skins as they grew. This control was a relatively slow process and the caterpillars continued to eat for some time before they died and could do considerable damage if they were in the latter stages of their growth. However this chemical did not affect the majority of other insects and wild life, had very low toxicity to fish and broke down readily in the soil. Over time, a natural virus and a bacteria which attacked the pine beauty was produced in commercial quantities and applied but again the control action was very slow and was best employed where the populations were just rising to danger level.
Groups: Aircraft in Forestry Work, Animal, Insect, Plant and Fungal species in forestry, Forestry Areas, Forestry in Action, George Dey Forestry Collection