Bark Beetles and Wood Borers

From Bugwoodwiki

Hagle, S.K; S. Tunnock; K.E. Gibson; and C.J. Gilligan. 1987. Field Guide to Diseases and Insect Pests of Idaho and Montana Forests. U.S. Department of Agriculture, Forest Service. State and Private Forestry, Northern Region. Missoula, Montana. Reprint 1990. Publication Number R1-89-54.

1 Pitch tubes or masses of pitch on outside of bark --- 2

1’ No pitch tubes or masses of pitch on bark. Orange, red or whitish boring dust in bark crevices --- 7

2 Under pitch mass, insect tunnel and, sometimes, larvae within the outer bark and phloem on Douglas-fir, ponderosa pine, and lodgepole pine --- Sequoia Pitch Moth

2’ Bark beetle gallery or adult beetles in tunnel (starting to build galleries) under bark in cambium beneath pitch knot or mass --- 3

3 On Englemann or Colorado blue spruce, boring dust, if present is red-brown, larvae, if present, in groups. Bark often removed by woodpeckers --- Spruce Beetle

3’ On pines --- 4

4 On ponderosa, lodgepole or pinyon pine; very large yellow-orange pitch tubes generally restricted to lower 3 feet of stem --- Red Turpentine Beetle (see also Root Diseases Key)

4’ Pitch tubes less than one-half inch in diameter, orange-red bring dust may be on bark; generally occuring above 3 feet on stem --- 5

5 On piñon and singleleaf piñon pines. Pitch tubes small, inconspicuous --- Piñon Engraver Beetle

5’ All pines; long vertical egg galleries with radiating horizontal larval galleries --- 6

6 Ponderosa pine in Southern Utah and Nevada; larval galleries somewhat meandering --- Roundheaded Pine Beetle

6’ In all pines except Jeffrey pine; Pitch tubes prominent; egg gallery with distinctive J-shaped hook at bottom and radiating horizontal larval galleries --- Mountain Pine Beetle

6’’ Jeffrey pine; egg gallery with distinctive j-shaped hook at bottom and radiating horizontal larval galleries --- Jeffrey Pine Beetle

7 Beetle entrance holes evident or red, orange or white boring dust on bark surface or on ground around tree --- 8

7’ Neither beetle entrance holes present, boring dust absent --- 16

8 Boring dust on bark is white and powdery; under bark, "pinholes" surrounded with brown or black stain go straightinto sapwood --- Ambrosia Beetles

8’ Boring dust on bark or ground orange or red --- 9

9 On Engelmann spruce or Colorado blue spruce, boring dust dark red; bark flakes may be removed from stem by woodpeckers --- Spruce Beetle

9’ On other tree species --- 10

10 On pines --- 11

10’ On other tree species --- 13

11 Ponderosa pine; gallery with serpentine pattern. Bark often removed by woodpeckers --- Western Pine Beetle

11’ Boring dust orange to red-brown; pitch tubes usually present; long vertical egg gallery with j-shaped hook at bottom and radiating horizontal larval galleries --- Mountain Pine Beetle

11’’ Galleries small with Y- or H-shape; boring dust yellow-orange; galleries clean of frass --- 12

12 On piñon and singleleaf piñon pines --- Piñon Engraver Beetle

12’ On other pine species --- Pine Engraver Beetles

13 Douglas-fir or western larch; boring dust red-orange; egg galleries vertical with horizontal larval galleries radiating in alternating groups --- Douglas-fir beetle (See also Root Diseases key)

13’ Not as described above --- 14

14 Junipers or western redcedar; vertical egg gallery with enlarged chamber on one end and horizontal larval galleries --- Cedar Bark Beetles

14’ On true firs; beetle entrance holes evident --- 15

15 Mostly in grand fir and white fir; horizontal egg gallery with vertical radiating larval galleries --- Fir Engraver Beetle (See also Root Diseases key)

15’ Mostly in subalpine fir; distinctive star-shaped gallery with central nuptial chamber and multiple radiating egg galleries --- Western Balsam Bark Beetle (See also Root Diseases key)

16 In dead trees of all species; galleries without pattern, packed with boring dust; round to oval holes sometimes present where larvae have bored into wood --- 17

16’ Dead or live trees; neither boring dust nor beetle entrance holes present --- Root Diseases key.

17 Broad, flat galleries tightly packed with fine boring dust. Larvae with two body segments behind the head that are flattened and much wider than the rest of the body; often fairly large --- Flatheaded Wood Borers (See also Root Diseases key)

17’ Round or oval galleries loosely packed with coarse boring dust. Large, cylindrically-shaped larvae have rounded heads only slightly larger than diameter of body --- Roundheaded Borers (See also Root Diseases key)