Phenology of gypsy moth flight

This map shows the time (month and week) of the peak flight of gypsy moth males predicted from 30-year average weather data by our phenology model. The model is a slightly modified GMPHEN model (Sheehan, K.A. 1992. User's guide for GMPHEN: Gypsy Moth Phenology Model. USDA Forest Service General Technical Report NE-158). It was implemented using BioSim software by Jacques Regniere (Canadian Forest Service, P.O. Box 3800, Sainte Foy, Quebec).

The recommended trap set and removal dates were estimated as follows: the date of 5% and 95% catch was modeled as a second order regression from the date of peak flight. Then the target date for setting traps was estimated using the regression for 5% catch minus 5 days, and the target date for removing traps was estimated using the regression for 95% catch plus 5 days. Plus-minus 5 days was used to account for possible variation in moth flight dates from year to year. Here are final equations for dates of trap setting and removal:

Set traps = 134 - 0.3*X + 0.00284*X² - 5
Collect traps = 223 - 1.14*X + 0.00537*X² + 5,

where X = julian day of peak flight.

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