A Guide to Common Forest Pests in Georgia

Terry Price, Forest Health Specialist, Georgia Forestry Commission

Pine Weevils

Weevils that damage pines in Georgia can be classified as seedling debarking weevils, terminal weevils and root collar weevils. Damage from weevils can be heavy in local areas where certain forestry practices favor their development.

Debarking Weevils

Weevils that are notorious for debarking pine seedlings are the pales weevil and the pitch-eating weevil.

The pales weevil, Hylobius pales, (Figure 14) prefers loblolly, shortleaf, pitch, and white pine seedlings. The adult weevils damage seedlings by chewing small holes on the stem above and below the ground. Seedlings are often girdled. The pitch-eating weevil, Pachylobius picivorus, is very similar to the pales weevil in appearance and habits (Figure 14B).

Serious damage from debarking weevils can be prevented or reduced if those conditions which favor weevil development are avoided. The weevils are attracted to recently cut pine areas where there is an abundance of pine stumps and buried slash. Adult weevils deposit eggs in roots of freshly cut pine stumps or buried slash. The larvae hatch in a few days and begin feeding beneath the bark. Upon emergence the new adults will seek out seedlings to feed on. Seedlings planted on or adjacent to these cutover areas are attacked by the newly emerging weevils and older adults.

The following guidelines will help reduce weevil damage:

  • Delay planting one year on cutover pine sites if the cutting was not completed before July.
  • lf planting cannot be delayed, the seedlings should be dipped in an approved insecticide (see appendix).
  • Delay clearcutting pine stands that are adjacent to recently planted pine plantations until the seedlings are big enough to withstand any feeding that may occur. Usually by age three-four seedlings are big enough to survive weevil feeding, however, damage can be extensive in some locations (Figure 14C).

Terminal Weevils

Terminal weevils in the genus Pissodes are very similar in appearance and habits. The adults are 3/16"- 5/16" in length depending on the species and vary in color from reddish brown to dark brown. The front wings (elytra) are marked with patches of white scales. Two common species that occur in Georgia are the white pine weevil (Pissodes strobi) and the deodar weevil (P. nenlorensis) (Figure 15).

The white pine weevil attacks the terminals of white pine in Georgia. Damage is done by the adults and larvae. The adults emerge in the spring and lay eggs in feeding pits on the terminals. Upon hatching the larvae tunnel in the cambium often killing stems. Puncture wounds made by the adults while feeding and laying eggs sometimes are so numerous that the stems are girdled (Figure 16). When a terminal is killed it is replaced by an adjacent branch which results in a crooked or forked stem. Damage can be severe at times (Figure 17).

The following management recommendations have been developed to reduce losses from the white pine weevil:

  • Plant seedlings on soils where the hardpan is three or more feet from the surface.
  • Regenerate white pine in mixture with hardwoods.
  • Use insecticides in Christmas tree plantings (see appendix).

The deodar weevil is active all winter and lays eggs in the fall and winter in small puncture holes chewed in the bark. The larvae have feeding habits similar to white pine weevil larvae in that stems are often girdled. Unlike the white pine weevil, the deodar weevil remains inactive during the summer in the ground litter.

Figure 14a - Pitcheating weevil adult and feeding damage
Photo by Robert Anderson, USFS

Figure 14b - Pitcheating weevil feeding on a 4 year old slash pine seedling
Photo by Terry Price, GFC

Figure 14c - Pitcheating weevil feeding damage
Photo by Terry Price, GFC

Figure 15 - Deodar weevil
Photo by Gerald Lenhard, LSU

Figure 16 - Terminal weevil feeding
Photo by USFS Archive

Figure 17 - Terminal weevil feeding
Photo by USFS Archive

Figure 18 - Deodar weevil pupa in its wood chip-lined pupal cell
Photo by Gerald Lenhard, LSU

Figure 19 - Terminal dieback of deodar cedar caused by environmental stress.
Photo by Terry Price, GFC

Deodar cedars are preferred hosts but loblolly, slash, shortleaf and longleaf pines are attacked. This weevil is often found breeding in pines that have been attacked by pine bark beetles and those infected with pitch canker. The wood chip cocoons made by the larvae are readily visible underneath the bark of infested trees (Figure 18)

No controls are necessary for the deodar weevil in forest stands. Deodar cedars growing in yards, parks and along city streets are hosts of this weevil and should be kept in a healthy condition. Deodar cedar terminals are often killed by sudden, extreme changes in temperature or by extended droughts (Figure 19). Damaged terminals are often attacked by the weevils.

The fungus Botriyosphaeria dothidea has been isolated from damaged terminals also and can cause a progressive dieback of the tree if the dead wood is not pruned properly.

Root Collar Weevil

The southern pine root weevil Hylobius aliradicis, occasionally damages the roots of seedling and sapling- sized loblolly and slash pines in southern Georgia. Damage appears to be worse in droughty years and on stressed trees. The larvae bore extensively in the root collar area of the trees. They pupate in wood chip cocoons similar to the other weevils (Figure 18). These pupal cells can he found under the bark at or below the ground line in dying trees.

White Fringed Beetle

This weevil historically has been a serious problem in cotton, peanuts, okra, velvetbeans. soybeans, and sweet potatoes. The larvae and adults have been observed feeding on more than 380 species of plants. The larvae feed on the roots, whereas, the adults feed on other plant parts above the ground.

The adults are dark gray with a whitish band along the outer wing margins. Larvae of this insect have recently been found feeding on the roots of newly planted slash and loblolly pine seedlings (Figure 20). Mortality does occur but appears to be insignificant at this point in time. However, due to the increasing number of farming failures, more and more agricultural lands are being planted in pines. This weevil has the potential of becoming a major pest on pine seedlings throughout Georgia and the South.

Control of the weevils in agricultural fields has been achieved by rotating crops and/or spraying with insecticides. Subsoiling or harrowing fields prior to planting trees could possibly provide some control by exposing the larvae to birds and other predators.

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