Dogwood Borer
Egg-Basically elliptical, the egg is blunt on both ends and very small. When first laid it is pale yellow, turning only slightly darker before the larva hatches
Larva-Off-white to cream colored, the larva has a reddish-brown head. The prothoracic shield characteristically has two reddish-brown dorsal spots. The larvae range in length from about 1.5 mm when newly hatched to 15 mm or more when mature. There are six stages.
Pupa -The pupa is light brown and about 10 mm long.
Host Plants -Flowering dogwood is the preferred host, but the dogwood borer has also been collected from oak chestnut, hickory, elm, willow, and pecan. However, it may be confused with at least two other species, Synanthedon corrusca Edwards and Aegeria pyri Harris.
Damage -On dogwood, attack is apparently confined to the trunk and limbs. In a single year one borer can completely girdle and kill a tree 10 cm in diameter, but death is more often brought about by the combined activity of several larvae and by successive infestations. Cultivated trees are usually more heavily infested than those growing in wooded areas.
Life History -The dogwood borer is the larval stage of a clearwing moth. A native pest, it is known by several other common names: pecan sesia, nine-bark borer, woody gall borer, oak gall borer, and others.
In the South, adult emergence occurs from late April to late October, peaking in mid-May. Eggs are laid singly onbark. A female may lay up to 116 eggs. Incubation usually requires 8 to 9 days. Newly hatched larvae become established only if they encounter a broken bark wound, a cracked callous area, such as a canker, or some site affording immediate protection. Feeding, confined to the cambium and bark, continues until winter. The dogwood borer then hibernates in the larval stage within its tunnel. Pupation takes place the following spring. Although there is only one generation per year, borers may be found in various stages of development throughout most of the year because eggs are laid over a period of several months.
Sprays should be applied in early June and repeated in 10 to 14 days. For specific chemical controls, see the current state extension service recommendations.