DesOchInsect

Failure Potentialdue to: 

Failure Potential due to Insect-caused damage and mortality

How are Insects Related to Hazard?: 

How are Insects Related to Hazard? Hazard: likelihood that a tree or a portion of a tree will fall Cause: weakened roots, stem, or branches (fungal decay, physical degradation); weather events ======================= Insects interact with fungal pathogens Insects directly kill trees and parts of trees

Bark Beetles: 

Bark Beetles -Signal Possible Hazard- Hundreds of species Opportunistic Frequently attack trees stressed from root disease, bole and root damage, drought Primary: Douglas-fir beetle, mountain pine beetle, western pine beetle, spruce beetle Secondary: Fir engraver; pine engraver; many others Check for root disease!!!

Bark Beetles: 

Bark Beetles General Signs, Symptoms, and Damage Patterns Boring dust Pitch streamers Gallery patterns under bark Fading or red crown Topkill Grouped mortality

Douglas-fir BeetleDendroctonus pseudotsugae: 

Douglas-fir Beetle Dendroctonus pseudotsugae Host: Douglas-fir One-year life cycle Prefers new windthrow or felled trees, and trees under stress Prefers trees larger than 12 inches dbh Check for root disease!!!

Douglas-fir BeetleDendroctonus pseudotsugae: 

Douglas-fir Beetle Dendroctonus pseudotsugae Signs, Symptoms, and Damage Patterns Boring dust on bark and in bark crevices around base of tree Pitch streamers higher up on bole Gallery patterns – larval galleries on alternate sides of vertical egg gallery

Slide7: 

Douglas-fir Beetle

Slide8: 

Douglas-fir beetle breeds in fire-damaged, diseased, and stressed DF. Decay is associated with beetles and wood borers. Saprot occurs first and heart rot follows. FP = Likely if: < 5 years dead < 50% saprot FP = Likely to Imminent if: > 5 years dead > 50% saprot

Fir Engraver Scolytus ventralis: 

Fir Engraver Scolytus ventralis Hosts: true firs One generation per year Associated with root-diseased trees Common during drought Check for root disease!!!

Fir Engraver Scolytus ventralis: 

Fir Engraver Scolytus ventralis Signs, Symptoms, and Damage Patterns Gallery patterns – horizontal egg gallery with notch in center Dead branch or group of branches (patch attack)

Slide11: 

Grand fir is predisposed to fir engraver-caused mortality by numerous factors. Sapwood decaying fungi are introduced and saprot quickly follows. FP = Likely if < 3 years dead FP = Likely to Imminent if > 3 years dead > 50% decayed

Slide12: 

Pines are attacked by several different species of bark beetles. Western pine beetle is especially active after fires in ponderosa pine and Ips beetles can be similarly active in ponderosa and lodgepole pines.

Mountain Pine BeetleDendroctonus ponderosae: 

Mountain Pine Beetle Dendroctonus ponderosae Hosts: pine species One-year life cycle Prefer trees under stress Stand density is key factor

Beetle-killed lodgepole pine: 

Beetle-killed lodgepole pine Lodgepole pine seldom have significant saprot while standing due to their thin bark. Blue stain does not reduce structural strength. However, roots rapidly decay once trees die. FP = Likely if < 5 years dead FP = Likely to Imminent if > 5 years dead

Western Pine BeetleDendroctonus brevicomis: 

Western Pine Beetle Dendroctonus brevicomis Hosts: ponderosa pine Two generations per year Egg galleries winding, packed with frass Often found in large, old, dominant pines

Red Turpentine BeetleDendroctonus valens: 

Red Turpentine Beetle Dendroctonus valens Hosts: pine species One-year life cycle Prefer trees under stress Generally don’t kill trees or affect them appreciably Common after fires

Pine Engraver Ips pini: 

Pine Engraver Ips pini Hosts: pine species Two generations per year Associated with logging slash and windthrown material Considerable mortality in young stands Topkill in large ponderosa pines

Slide18: 

Beetle-killed ponderosa pine can fail due to stem saprot or decayed roots. FP = Likely for pine <16” dbh < 5 years dead or < 50% saprot pine >16” dbh < 10 years dead or < 50% saprot FP = Likely to Imminent for pines exceeding these guidelines

Spruce BeetleDendroctonus rufipennis: 

Spruce Beetle Dendroctonus rufipennis Host: Sitka spruce, Engelmann spruce One- to three-year life cycle (dependent upon temperature Prefers new windthrow, felled trees, and trees under stress Check for root disease!!!

Spruce BeetleDendroctonus rufipennis: 

Spruce Beetle Dendroctonus rufipennis Signs, Symptoms, and Damage Patterns Boring dust on bark, in bark crevices, and around base of tree Masses of pitch may accumulate around entrance sites Gallery patterns – larval galleries on alternate sides of vertical egg gallery

Beetle-killed Engelmann spruce: 

Beetle-killed Engelmann spruce Bark beetle-killed spruce can be especially dangerous due to the high incidence of tomentosus root and butt rot in spruce. Without root disease, FP = Likely if spruce dead < 5 years.

Wood Boring Insects : 

Wood Boring Insects Signs, Symptoms, and Damage Patterns Boring dust on bark and in crevices Gallery patterns – randomly winding, gradually widening gallery with no perpendicular secondary galleries Galleries packed with fine boring dust (concentric rings) or long, angular fibers Creamy, flattened larvae with “horse-shoe nail” shape

Flat-headed Wood Borer : 

Flat-headed Wood Borer Frass has appearance of concentric rings larva adult

Slide24: 

Sapwood decay on dead trees includes gray saprot (pouch fungus) and others. Decay is aggressive. FP = Likely if: < 50% decay < 3 years dead for true firs, hemlock, and spruce < 5 years dead for pines and DF. FP = Likely to Imminent if: > 50% decay > 3 years dead for true firs, hemlock, and spruce > 5 years dead for pines and DF.

Carpenter AntsCan severely weaken tree base: 

Carpenter Ants Can severely weaken tree base Large sawdust pile at base of tree Big black ants coming and going Honeycombed wood

Carpenter Ant Signs: 

Carpenter Ant Signs

Slide27: 

Woodpecker feeding on carpenter ants in this beetle-killed spruce indicate a dead tree with Likely to Imminent failure potential

Slide28: 

Balsam woolly adelgid causes mortality throughout the subalpine fir host type. FP = Likely if < 3 years dead <50% decayed FP = Likely to Imminent if > 3 years dead or > 50% decayed

Slide29: 

Defoliators including tussock moth and budworm can severely damage Douglas-fir and true fir during outbreaks. Tops are killed and bark beetles become active several years into outbreaks, causing mortality. Dead trees and tops have likely FP, until tops have significant saprot and dead trees are no longer sound; then FP = likely to Imminent