Ips Engraver Beetles

Ips spp.

Order Coleoptera: Family Scolytidae

Description: Adults are dark brown, cylindrical beetles.  Ips can be distinguished from other bark beetles by the conspicuous cavity on the wing covers at the rear of the body.  There are three to six spines on each lateral margin of this cavity, depending on the species.  Three species commonly attack pines in Georgia.  Larvae are small, white, legless and found in galleries under the bark.  Galleries of Ips beetles are usually H-shaped or Y-shaped.

Hosts: Various species of pines

Damage:  Adults and larvae bore under the bark making galleries in the cambium.  Various Ips species may infest pines along the entire trunk.  Tops of infested trees fade, brown, and shed needles.  This fading usually progresses downward from the tree top.  Treetops and sometimes whole trees die.  Damage may progress over an extended period of time (from a few weeks to several months).

Life Cycle: The beetles overwinter in duff and litter, occasionally under bark.  They breed in freshly cut pine wood or trimmed branches.  Males attack trees first and produce an attractant which draws other beetles.  Eggs are laid in galleries excavated by adults under tree bark.  Adult galleries are usually free of frass.  Larval galleries radiating from the central tunnel are packed with frass.  Ips have two to four generations per year depending on location and temperature.

Control: Keep trees vigorous to reduce infestation.  Healthy trees often "pitch out" attacking beetles. Remove and utilize or destroy dead and dying trees immediately.  Spray trees adjacent to infested trees with residual insecticide to prevent attack.  Chemical control usually is not practical in forest situations.

Photo by Forest Insects and Their Damage Photo CD vol. 1 no. 88. Gerald Lenhard, Louisiana State University.

Photo by Forest Insects and Their Damage Photo CD vol. 2 no. 12. Ronald Billings, Texas Forest Service.