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Pine Sawyers – Monochamus spp.

Pine Sawyers (Monochamus spp.) Latin Name: Monochamus spp.) Common Name: Pine Sawyers Appearance:
  • Adults are huge beetles (approximately one inch long), black to brownish-grey with white speckling, and have extraordinarily long antennae that are one to three times the length of the body
  • Larvae: up to 1 inch long; white grubs without legs
Host plants: Pines (Pinus species), spruces (Picea species), firs (Abies species), and Douglas-fir (Pseudotsuga menziesii). Damage caused by Pine Sawyers: Larvae burrow deeply into the sapwood and heartwood of dying and recently deceased trees. They do minimal harm to living trees but are typically connected with fuel and house logs. The larvae of this roundheaded borer are elongate, segmented, legless grubs with brownish heads.Adults do minimal damage by feasting on needles and shooting bark. This genus includes the principal vectors of the pine wilt nematode, the cause of pine wilt illness in the Midwest and other world areas; however, this is unknown in the region. Life history and Habits: Adults are present throughout the warm months but are most frequent in late summer. These large, harmless insects frequently land on persons working or playing in the woods. They eat on treetops and deposit eggs in little craters carved in the bark of branches and, especially, trunks. The larvae dig extensive tunnels just beneath the bark, packed with fibrous frass. Large mounds of sawdust and fibre frequently gather beneath affected trees or longs. Larvae enter the woods and tunnel for several months. Each year, there is one generation.