PORTLAND PRESS HERALD • June 2, 2025
A government-funded campaign has begun spraying insecticides and biological agents on 240,000 acres of Maine’s North Woods infested with spruce budworm, a voracious forest pest that killed millions of spruce and fir trees during its last population explosion. JBI Helicopters began spraying tebufenozide over 9,000 acres in far western Maine on Thursday. The spraying, approved by the Board of Pesticide Control in April, could last through June 25 of this year. The tebufenozide (MIMIC) kills the budworm caterpillar by triggering a premature molt. Any caterpillar that eats it will die, however, including those that turn into beneficial moths and butterflies. A biological agent, Bacillus thuringiensis kurstaki (Btk) is also authorized for use, but will likely be applied in much smaller amounts. It destroys the caterpillar’s gut lining.