The small larvae of the Round-headed Apple Tree Borer are responsible for many tree deaths thanks to their interruptive tunneling.
Adult Round-headed Apple Tree Borers are attractively colored and striped. They are not exclusive visitors to apple trees despite their name. Ash, plum, pear, hawthorn, serviceberry, and quince trees are also targets. Adults feed on tree leaves, but their young are the devastating force that ruin the hope of home-grown fruit. Females lay fertilized eggs into the lower part of tree trunks. The newly hatched larvae begin chewing their way deeper into the trunk. They cast out the digested wood as frass, a sawdust-like material usually found at entry holes. Tunneling across the 'veins' of the tree breaks the upward and downward flow of xylem and phloem, the water and liquid food a tree needs to have in all of its parts to survive. Free-flowing sap can sometimes also be seen at entry points, signs of the tree losing its nutrients. Larvae can remain inside the tree for years while they grow and develop. Many larvae in one tree can cause it to weaken and die via starvation or infection.
Spraying trees (trunk and leaves) with insecticide in late spring/early summer helps poison adults and deter any surviving females from landing on trunks to lay eggs. Painting the lower part of a tree trunk with whitewash helps make it easier to see indicators of larval infiltration. If caught early, digging out the dead bark at an entry point and poking wire into the larval hole may effectively kill it, though this time-intensive manner of control is not easy, nor is it practical in orchards. Multiple applications of insecticide throughout the summer can reduce and protect trees and is the most common form of control.
Scientific Name: Saperda candida
Size (Adult; Length): 10mm to 21mm (0.39in to 0.82in)
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Antennae: Beetles have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and mandibles (jaws).
Thorax: Holds the three pairs of legs as well as vital internal organs.
Elytron: One of two wing cases on a Beetle that protects its wings (plural: elytra).
Wings: Appendages used for flying and kept under the elytra until needed.
Abdomen: Houses organs related to circulation, reproduction, and excretion.
Legs: Beetles have three pairs of legs located at the thorax, numbering six legs in all.