Pest Predictions for 2012

The Iowa caucuses are behind us and political prognosticators in full glory.  Not to be left out, we have our own 2012 predictions.  Our predictions are on the 2012 landscape insects and diseases – no politics involved.  Two thousand and eleven was laden with garden pestilence.   The following are some of the more interesting contenders for 2012. 

National Significance:

Thousand cankers of black walnut has the potential to wipe out black walnuts in the United States.  This insect/disease complex appeared in Colorado nearly ten years ago but is the most prevalent in Boulder where there was a large population of planted walnuts.  The disease has slowly worked its way up and down Colorado’s front-range.  We had hoped that it wouldn’t spread eastward into the native walnuts of the mid-west.  However, in July of 2010 the disease was discovered in Knoxville, Tennessee.  In 2011, discoveries were made in Virginia and eastern Pennsylvania.   This disease will continue to kill walnuts in Colorado, however the epidemic is slowing somewhat.  We are hopeful that a resistant population of walnuts can be indentified and bread. 

Japanese beetles are a relatively new entry.  No stranger to the eastern United States these colorful shiny green beetles have taken up residence in Denver.   Japanese beetle is both a serious pest of turf grass and ornamental plants. In the turf, Japanese beetle larvae (grubs) feed on the roots.  The adult beetle palette includes some 300 plant species, but prefers roses, linden and Virginia creeper vine.   

Regional Significance:

Turf mites are a shoe in.  Last year winter with little to no snow cover (least snowiest since 1882) mites had free reign on our lawns.  Many lawns either freeze-dried or were killed by mites during the winter.  As spring approached, only then, was the damaged realized when the lawns failed to green up.  Looking to 2012, even with snow cover, mites are still present in a “resting state” ready to resume feeding on warm winter days.  Expect susceptible lawns to have significant mite activity this spring. 

Also a sure bet are aphids.  For the past several years, we have seen a vast increase in aphids feeding on pines and spruce.  Infested trees are easily detected by a shiny appearance and sticky foliage.  Aphids can be found feeding on pine needles even during the winter months.  Aphids are likely to be significant in 2012 both on evergreens and leafy trees and shrubs. 

The soft scale insects have increased throughout the United States.  Our eastern Colorado nemesis is European elm scale.  Cars parked under American elms become sticky from the resulting scale honeydew production.   Trees look sickly and limp.  From the history books, striped pine scale is starting to make a comeback especially on Scotch and mugho pine. .

Elm flea weevil is a relatively new candidate on elms.  First discovered in the mid-west United States in 2003 it quickly spread westward and has impacted elms along Colorado’s front-range for the past 3 to 4 years.  The insects are tiny (1/8” long) and hard to detect.  The damage looks a lot like elm leaf beetle with heavy feeding on affected elm leaves. 

Stay tuned, 2012 will be an active pest year.