Trees can become afflicted with problems that can change their appearance and overall health. Iowa State University Extension and Outreach horticulturists offer tips on fighting these issues. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
My magnolia is infested with magnolia scale. What are my control options?
Magnolia scale (Neolecanium cornuparvum) is the largest scale insect in Iowa. Adult magnolia scale females are pinkish orange to brown, elliptical and up to one-half inch in diameter. Females give birth to their young (known as nymphs or crawlers) in late summer.
Sap feeding by the scales causes stress to heavily infested plants and can result in stunted growth, yellowish foliage, branch dieback, or death of the plant. Magnolia scales produce large quantities of honeydew (sugary excretion) that accumulate on the tree’s leaves and twigs. Sooty mold, a black fungus that grows on honeydew, turns the honeydew-covered leaves and twigs black.