In this period of rapidly changing climate and increasing
threats from invasive species, forecasts of when
and where pests will emerge can help arborists stay
ahead of the curve. The USA National Phenology
Network (USA-NPN) offers "Pheno Forecast" map
products for a growing number of insect pests,
including emerald ash borer (Agrilus planipennis).
Pheno Forecast maps indicate, for a specified day,
the status of the insect's target life-cycle stage in
real time across the contiguous United States. Maps
are available via the USA-NPN visualization tool
and the USA-NPN website. Pheno Forecast maps
are based on models that estimate the status of a
pest's life stage using heat units (degree-days), which
accumulate when temperatures fall between the
stage's developmental temperature thresholds.
In collaboration with researchers at Oregon
State University, the USA-NPN released an
enhanced set of Pheno Forecast maps for
emerald ash borer in spring 2023. The new fore-
cast products offer several enhancements:
• Forecasts are available for both egg
hatch and adult emergence.
Enhanced Forecasts of
Emerald Ash Borer Activity
By Theresa Crimmins (Director), Erin Posthumus (Outreach Coordinator and US Fish &
Wildlife Service Liaison), and Alyssa Rosemartin (Partner and Application Specialist) of the
USA National Phenology Network; and Brittany Barker (Entomology Research Associate)
and Len Coop (Associate Professor of Horticulture) from Oregon State University
Emerald Ash Borer. Photo by David Cappaert, Bugwood.org.
• Forecasts are available for the entire
year, allowing you to anticipate when
the events are likely to occur several
months in the future. As the year pro-
gresses and the window of activity
passes, the map shifts to indicate
the date when the event occurred.
• Maps exclude regions where tem-
peratures are too hot or too cold
for the species to persist.
Get notified when emerald ash borer
will be active in your area! Receive
advance warning of actionable activity
for your pest of interest. Sign up to
receive email notifications approxi-
mately two weeks and six days before
the two events—egg hatch and adult
emergence—occur at your location.
12 CityTREES
