The following is a prediction of the stage of development of several species of insects, based on the blooming of bridal wreath spirea or Vanhoutte spirea (Spiraea x vanhouttei). This information is from Coincide by Donald A. Orton. The 190-page book published in 1989 is available from the Labor of Love Conservatory, 468 S. President, Suite 103, Carol Stream, IL 80188-2894; (630)668-8597.
Phenology information is listed for scouting and identifying potential problems. It helps you know when to look for certain pests. It should not be used as a biological calendar spray schedule.
Birch leafminer young larvae
Elm leaf beetle young larvae
European pine sawfly feeding larvae
Gypsy moth feeding larvae
Pine needle scale crawlers (first generation)
Full to late bloom:
Lilac (ash) borer newly hatched larvae
Oystershell scale (brown) crawlers
Bronze birch borer newly hatched larvae
Most blossoms brown, a few still white:
Flat-headed appletree borer larval hatch
Peach tree borer newly hatched larvae
Viburnum borer newly hatched larvae
Oystershell scale (gray) crawlers