Dogwood Borer

• The dogwood borer, referred to scientifically as Synanthedon scitula, is off-white with a reddish head and reaches a mature length of 5/8 inch. The adult is a clearwing moth that looks like a wasp and lays eggs on the dogwood bark. The borers can only infest the plant if they locate a wound in the bark. Upon entry the borer feeds on the cambium, causing branches on the entire tree to die. Leaves often turn red and drop early and bark sloughs off around borer holes. Established plants lack vigor and develop rough, knotty areas along the branches and trunk. Prevent borer problems by using proper cultural practices and avoid wounding the tree. Insecticides that contain permethrin can be applied regularly to control the borer.
  
  

Dogwood Sawfly

• The dogwood sawfly, Macremphytus tarstus, is an especially prevalent pest of gray dogwood. The larvae of the wasp-like sawfly takes on several forms ranging from a small translucent yellow to a final stage when it is an inch long and creamy yellow with a shiny black head. The larvae group on the undersides of leaves and can cause severe defoliation before they stop feeding to overwinter in wooden structures. Sawfly larvae can be controlled by hand removal or with chemical treatment using horticultural oil, insecticidal soaps or traditional insecticides while larvae are still actively feeding.
  
  

Scales

• Several different scale insects may attack dogwood. Scales vary in appearance but typically resemble small, dark bumps on leaves or stems, where they feed on sap. Heavy infestations can cause leaf yellowing and branch dieback. If scales are a problem, thoroughly apply horticultural oil in the spring before new growth appears and again after flowering.
  
  

Dogwood Club-Gall Midge

• The dogwood club-gall midge adult, a small fly, lays eggs in tiny, terminal dogwood leaves. The larvae hatches, enters the shoot and feeds, creating a tubular swelling, or gall, where it is present. A light infestation of this pest is simply cosmetic, but a heavy infestation can stunt the dogwood. Address this pest by pruning and destroying infected twigs before the larvae emerge from the galls in fall.
  
  

Dogwood Twig Borer

• The dogwood twig borer adult is a slender, long-horned beetle about 2/3 inch long with three black spots on its thorax. The adults emerge in early summer, girdle twigs and lay eggs in the created crevices. Pale-colored larvae hatch and tunnel along the center of twigs. Twig borer activity causes leaf wilt on individual twigs. Treat plants by pruning off twigs below the girdling and destroy these infested branches.