Forest Insect and Disease Newsletter

Aerial survey

Spruce budworm defoliation map of MinnesotaSince the early 1950s, the aerial detection survey has been a valuable tool for monitoring forest defoliation and mortality and possible disease or insect outbreaks across the 16 million acres of forest land in Minnesota. The Pest Conditions Report This is a PDF file. You will need Adobe Acrobat Reader to download it. is a summary of the results of the 2013 aerial survey.

In the report, you will find the name of the pest or causal agent and corresponding maps with polygons and acreage of damage or mortality caused by the pest. Some facts gleaned from this year's aerial survey:

  • Eastern larch beetle has been in outbreak mode for 14 years and has destroyed 18 percent of the state's tamarack population
  • Although defoliation by forest tent caterpillar was relatively light, defoliation was recorded on more than one million acres
  • Normally an outbreak pest, a continuous infestation of spruce budworm has occurred in northeastern Minnesota since 1954
  • Compared to 2012, recorded acreage of aspen decline decreased by 27,000 acres
  • Drought continues to impact Minnesota's forests