Granulate Poplar Borer – Agrilus granulatus

Granulate Poplar Borer (Agrilus granulatus) Latin Name: Agrilus granulatus Common Name: Granulate Poplar Borer Appearance: Adult: Olive brown beetle with a bit of flattening, somewhat shiny, slender appearance and a length of 7 to 11 mm Males are somewhat slimmer and shorter than females. Short, recumbent, pale pubescence covers the whole body. Each elytron has three thick white to golden hair patches, one in the basal depression, one in front of the midpoint, and the other towards the apical fourth. These markings identify this species from A. g. litragus Barter and Brown in living beetles. Larva: 27 to 40 mm length, elongate, skinny. White save for brown mouthparts and anal forceps, body flattened with enlarged prothorax. Host plants: In their development, Lombardy poplar, eastern cottonwood, and black cottonwood were used. Territory: Throughout the United States Damage caused by Granulate Poplar Borer: Early signs of assault include thin crowns and dead branches. Trees of all sizes, from saplings to sawlogs, may be assaulted. Although sap spots emerge on the bark occasionally, minor apparent surface damage signals an early infection. By removing the bark, extensive galleries can be revealed. The cambium galleries range from tight zigzag loops extending vertically to meandering without much pattern. Emerging beetles leave tiny D-shaped holes in the bark. Infested trees may die immediately or slowly over several years, depending on external pressures. The borer is now being blamed for the demise of numerous previously ascribed trees to drought. Life history and Habits: Adults emerge throughout June and July, feeding on the leaves of host trees. Females lay their eggs in fissures in the rugged bark of sensitive trees’ branches and trunks. They favor trees that have been badly harmed by drought, disease, or poor site circumstances. Larvae feed and develop beneath the bark most of the time but occasionally burrow into the wood for a brief period before returning to the cambium. In October, larvae bore 2.5 to 5 cm into the wood obliquely, a few centimetres up or down, before bending back to within 3 to 8 mm of the wood surface. Pupation usually starts in May and lasts for around two weeks. The life history is unknown; however, it appears to have a generation of one or two years, comparable to A. g. liragus.