Univ. of Md. Extension personnel report quite a bit of activity from planthoppers. The pest has been identified on various plants including hydrangea, zinnias, veronica, roses and monarda. The planthoppers, especially the nymphs, produce a lot of waxy material as a protective cover. They are sometimes mistaken for mealybugs.
Most often control is not necessary. Extension officials said the infested plants can be hosed off with water to remove leafhoppers. Insecticidal soap can be applied if populations are extremely high.
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