How to Read the Maps

Risk Level and Source Region Explanations

LOW RISK (Green)
ACTION: Isolated action only.
PERCENTAGE: 15% probability of experiencing an insect flight resulting in increased trap counts and presence of new moths.
ISSUED WHEN: Weather conditions are not optimal for widespread flights, but are of enough concern to issue a risk.

MODERATE RISK (Yellow)
ACTION: Begin scouting as new migrants may appear on a scattered basis.
PERCENTAGE: 30% or greater probability of experiencing an insect flight resulting in increased trap counts and presenceĀ of new moths.
ISSUED WHEN: A favorable weather pattern exists (south/southwest winds, scattered/widespread precipitation). Knowledge of current insect activity in the source region is present.

HIGH RISK (Red)
ACTION: Immediately scout all fields currently at a susceptible stage to insect damage.
PERCENTAGE: Over 50% probability of experiencing an insect flight resulting in increased trap counts and presence of new moths.
ISSUED WHEN: An optimal weather pattern exists (strong south/southwest winds and expected precipitation). Crop damaging insects are active in the source region but may move to a new area based on the existing crop stage.

Note: Just because the weather pattern is most conducive to insect migration does not mean an increased (Moderate/High) risk level will be issued. Generational aspects of the insects, crop stage both in the source region and expected drop zone region, and insect activity all play an important role in what risk level is issued and where.

INSECT SOURCE REGION (Brown)
Indicates where wind flow (usually south/southwest) is expected to originate and where insect trap counts signal a presence of widespread moth activity.

Explanation of Symbols and Risk Levels

  • Low Pressure Center Low Pressure Center — Usually associated with clouds, rainfall and upward moving air. Winds always blow counterclockwise.
  • High Pressure Center High Pressure Center — Usually associated with clear or partly cloudy skies, no rainfall and downward moving air. Winds always blow clockwise.
  • Cold Front Cold Front — Always connected to a low pressure center and usually trails to the south or west. Precipitation is most often focused along a cold front and is a favorable region for insects to drop out of the sky.
  • Warm Front Warm Front — Always connected to a low pressure center and usually positioned to the east or southeast. The heaviest precipitation occurs to the north of the warm front and can also be a favorable region for insect drop zones.
  • Black Directional Arrow Black Directional Arrow — Probable path of insect movement.