Ips beetles
Natural History
Adult and larval galleries of Ips avulsus
Photo credit: Ronald F. Billings, Texas Forest Service, Bugwood.org
Ips beetles are a genus of pine bark beetles represented by three species in Florida: Ips avulsus, Ips grandicollis, and Ips calligraphus. These beetles usually attack only a small number of trees at one time but under the right conditions, Ips beetle attacks can become more widespread. Ips beetles prefer to attack weakened trees and thrive in hot weather.
Adult beetles invade a new host tree and soon the females lay eggs. Several days later the eggs hatch and the larvae begin eating the inner bark of the host tree. Adults carry a fungus into the tree and use this fungus serves as part of their food source.
Trees are damaged by the insects as they excavate galleries in the phloem. These galleries cut the phloem cells that transport food throughout the tree. The blue stain fungus grows from the galleries into the wood, blocking the xylem cells that carry water through the tree. Eventually the tree dies. Healthy trees can fight off an attack by producing lots of pitch that acts as a barrier against the beetles.