Pine Bark Beetles
|
Southern Pine Beetles
Dendroctonus Frontalis |
Black Turpentine Beetle
Dendroctonus Terebrans |
Red Turpentine Beetle
Dendroctonus Valens |
Engraver Beetles |
Ips spp. |
| USDA Forest Service. 1979. A guide to common insects and diseases of forest trees in the northeastern United States. Northeast. Area State Priv. For., For. Insect and Disease Management., Broomall, PA. p. 123, illus. |
These beetles constitute the greatest insect threat to our southern pine forest. Adults cause damage by boring into the cambium of living trees and constructing tunnels, which eventually may girdle and kill the trees.
The southern pine beetle is the most destructive bark beetle in the group. During severe outbreaks, it has destroyed millions of board feet. Loblolly and shortleaf pine are preferred hosts, but it will attack any southern pine species.
The black and red turpentine beetles prefer trees of reduced vigor, but are capable of attacking apparently healthy trees as well. The most destructive populations usually develop in stands disturbed by logging, lightening, or fire. The black turpentine beetle attacks all southern pine species, although it affects loblolly and slash the most severely. The red turpentine beetle attacks all pine species within its range, and occasionally attacks spruce, true firs, Douglas-fir, and larch.
Engraver beetles are second only to the southern pine beetle in the mortality they cause. They usually prefer trees that have been weakened by lightning or other damage, or infest fresh slash remaining after logging operations. Ips calligraphus, Ips grandicollis, and Ips avulsus attack all southern pine species in their ranges. Ips pini attacks all pines in its range and several spruce species, as well.
The number of generations per year depends on the location and species of bark beetle.
| Insect | Description | Mode of Attack | Sign of Attack |
| Southern pine beetle | Brown-black beetle 1/8 inch long, rounded posterior, with minute notch in front of head when viewed from above. | Bores under bark and girdles southern pines. Attacks middle and upper stem in fall and winter, and lower stem in spring and summer. | Small white pitch tubes on bark or just boring dust. S-shaped and criss-crossed tunnels under bark. |
| Turpentine beetles | Light reddish brown or black beetles from ¼ to 1/3 inch long with rounded posterior. | Girdles inner bark of stumps and butts of larger pines. Larvae feed in groups. Usually found after fires, logging, or other disturbance. | Large pitch tubes on bark surface at tree base. Tunnels in inner bark are rather shapeless cavities. |
| Engraver beetles | Reddish dark-brown or black beetles less than ¼ inch long with a posterior that looks cut off and scoop-shaped. | Bores under the bark and girdles small commercial trees. | Small reddish pitch tubes on bark surface or just boring dust in cracks of bark or on ground. Y- or H-shaped tunnels parallel with wood grain on inside bark. |
Galleries
Clemson University - USDA Cooperative Extension Slide Series, |
Adult(s); Side view taken using an Auto-Montage digital microscopy system.
© 2002, 2003 by the University of Florida and may be freely used for educational purposes as long as credit is given to the University of Florida and, if space permits, the photographer. Any commercial use requires written permission of the Chairman, Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32611-0620.
David T. Almquist, University of Florida |
Adult(s); Close-up of an adult beetle.
Ladd Livingston, Idaho Department of Lands |
Galleries; newly initiated gallery with adults present
Scott Tunnock, USDA Forest Service |
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