Round two of the aerial gypsy moth spraying began Tuesday morning in West Hamilton, Ancaster, Dundas, and Flamborough.
It will continue Wednesday morning from 5 -7 a.m. The third and final spray date has not yet been released.
The helicopters spray a bio-pesticide to help manage the gypsy moth infestation.
The pesticide is organic and specifically targets gypsy moths and other caterpillars.
Officials say it will not have any health impacts on humans, pets, or other animals.
Burlington, Mississauga and Toronto are also spraying to stop the caterpillars from destroying trees.
Diana Weeks has the story from the first round of sprays:
