Ips pini

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Order	Coleoptera
Suborder	Polyphaga
Infraorder	Cucujiformia
Superfamily	Curculionoidea
Family	Curculionidae
Subfamily	Scolytinae
Tribe	Ipini
Genus	Ips

Scientific Name

Ips pini

Common Name

pine engraver

Authors: Christine Leduc and Laura Timms, Faculty of Forestry, University of Toronto. Article built on previous submission by G. Keith Douce from the University of Georgia.

Identification

Adult beetles are shiny reddish-brown to black and very small (only about 3 to 6 mm long). When you look down at the beetle from the top, its head is not visible; this is useful when trying to distinguish it from other beetles in the field. The larvae are white with a brown head.

Hosts

Ips pini is found on a variety of pine species. Lodgepole pines and ponderosa pines are its favorite host plants. It prefers to attack pole-sized trees (5-8 inches in diameter).

Geographic Distribution

Ips pini is distributed throughout North America, from northern Canada and Alaska to northern Mexico. This engraver beetle is a native pest.

Damage

Pine engraver beetles are not aggressive stand killers, but more often target trees previously damaged by logging, windthrow, fire, lightning, ice, etc. Their presence is indicated by brownish sawdust masses on the bark; this is boring dust pushed to the outside of the tree by the beetle. Underneath the bark, the beetle constructs egg galleries in Y or H-shaped patterns. The foliage will fade after beetle attack and treetops will turn yellow before tree mortality, after which they will appear red. These beetles frequently carry a fungus known as blue stain fungus, which disrupts movement of fluids within a tree and can give the wood a blue appearance.

The engraver beetle may be confused with the mountain pine beetle, Dendroctonus ponderosae. Both beetles attack similar host tree species, cause trees to turn red, and can even sometimes attack a tree in conjunction.

Life Cycle

Ips pini has four life stages: egg, larva, pupa, and adult. Male beetles bore through the bark and attract females with chemical attractants known as pheromones. This causes an accumulation of beetles on a single tree, resulting in a mass infestation. After mating, female beetles bore egg galleries in the vital layer of the tree. There are three generations a year, each marked by a period of phloem and sapwood consumption by the larvae. These bark beetles spend the winter as adults hiding in the ground or in bark crevices and emerge in the spring looking for trees that will accommodate them.

Control and Management

The key to preventing tree damage by Ips pini is to use sustainable forest management, which promotes forest health. Most problematic pine engraver infestations come secondarily to disturbances, such as windthrow, drought, logging, fires, construction, urban sprawl or other human activities. These disturbances provide ideal environmental conditions for a large Ips pini population. A method of physical control involves removing all the dying trees and having them destroyed by burning them before spring. In plantations, it is not uncommon to pile up a supply of freshly cut trees to attract the beetles and keep them away from standing trees. Natural controls involve predation by birds and parasitism by wasps, but these will not prevent outbreaks.

Image Gallery

Sawdust on bark indicating the presence of ''Ips pini''

Infestation marked by group kill

Egg galleries

Evidence of bark beetle presence: exit holes in bark