It is much easier to plan when
to treat your trees for pest insects if you know
when they will be most susceptible to treat-
ment in your location. Further, timing pesticide
treatments to coincide with peak susceptibil-
ity reduces the amount of chemicals needed.
The USA National Phenology Network's Pheno
Forecast maps show when management actions
should be taken for key pest species including
emerald ash borer (Agrilus planipennis), lilac
borer (Podosesia syringae), hemlock woolly
adelgid (Adelges tsugae), and winter moth
(Operophtera brumata). These maps, available at
2.5 km spatial resolution, are updated daily and
are available six days into the future (Figure 1).
Pheno Forecasts are based on published growing
degree days (GDD) thresholds for points in pest
life cycles when management actions are most
effective. Using the USA National Phenology
Network (USA-NPN) daily accumulated GDD
maps, which display heat accumulated above
a base temperature from Jan 1, locations are
shaded as not yet approaching time to treat,
approaching time to treat, time to treat, and past
time to treat by their heat accumulation status
relative to the threshold for a specific pest.
Pheno Forecast maps are available on
the USA-NPN website and through
the USA-NPN visualization tool.
USA-NPN Daily
Pest Forecasts
Guide Timing
of Treatment
for Insect Pests
By Theresa Crimmins, Kathy Gerst,
Lee Marsh, Erin Posthumus, Alyssa
Rosemartin, and Jeff Switzer
Figure 1: Emerald Ash Borer six-day
Pheno Forecast for April 9, 2018.
Photo: Adult Emerald Ash Borer, photo
by David Cappaert, Bugwood.org
14 CityTREES
