Adult flatheaded appletree borer emergence holes are D-shaped, whereas adult rounded appletree borer emergence holes are (you got it) round.Both species’ adult females lay eggs in fissures or slits in the bark, usually towards the base of plants.
Flatheaded appletree borer adults are around 12 mm long, have a metallic sheen, and are brown to grey in hue.
Larvae are 25 mm long when fully mature, and they form lengthy, twisting, torturous tunnels that can girdle and destroy huge branches and/or young trees.
Eggs hatch into legless, white & gray larvae 3 to 4 mm long
Host plants:
Saskatoon, apple, hawthorn and mountain ash.
Territory:
Most Roundheaded Appletree Borer states and provinces are in eastern North America.
Damage caused by Roundheaded Appletree Borer:
Damage from feeding can girdle the stems and produce die-back. The damage appears to be quite comparable to that caused by the woolly elm aphid. Cracking and cracks in the bark of the lower stem, which are not linked with the woolly elm aphid, identify this insect’s damage. Because the larvae are tiny at first, harm may not be visible until the insect’s second or third year of development. Plants inside rows may be mainly healthy, with only a few plants being impacted. Newer plantings are likely to be more vulnerable than older ones.
Life history and Habits:
It takes three years to complete the life cycle. Adult beetles are light brown in colour with two white stripes running down the rear of the body. The antennae are at least as long as the body, which is 20 mm long. Females lay eggs in slits at the base of saskatoon stems throughout the months of June and July, when adults are present. The larvae feed for two to three years on the inner bark and sapwood, during which time they dig huge tunnels in the stem. Pupation takes place inside the tunnels, with adults emerging in June. Adults are generated every year because populations are not coordinated.
