Bridal wreath spirea, or Vanhoutte spirea (Spiraea x vanhouttei), is blooming in northern Illinois, and professional horticulturists should be watchful for the following being susceptible to control activities. Full bloom: Birch leafminer young larvae; elm leaf beetle young larvae; European pine sawfly feeding larvae; gypsy moth feeding larvae; pine needle scale crawlers (first generation), black turfgrass ataenius (first generation). Full to late bloom: Lilac (ash) borer newly hatched larvae; oystershell scale (brown) crawlers. Finishing bloom: Bronze birch borer newly hatched larvae. Most blossoms brown, still a few white: Flatheaded appletree borer larval hatch; peachtree borer newly hatched larvae; viburnum borer newly hatched larvae. Bloom finished: Oystershell scale (gray) crawlers.
Euonymus scale is in the newly hatch nymphal or crawler stage in central and southern Illlinois. These crawlers are lemon yellow and easy to spot on the foliage. Most contact insecticides are effective, including insecticidal soap, summer spray oil, acephate (Orthene), bifenthrin (Onyx, Talstar), and cyfluthrin (Tempo). Be sure to get thorough coverage to achieve a high level of control.