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SOUTHERN PINE BEETLE

James R. Baker and S. Bambara, Extension Entomologists

CAUTION: This information was developed for North Carolina and may not apply to other areas.

SOUTHERN PINE BEETLE, Dendroctonus frontalis(Zimmerman), Scolytidae, COLEOPTERA

General Information

The southern pine beetle is short-legged, stout, and about 1/8 inch long. The fore part of the head is notched, and the hind end of the body is rounded. Mature beetles are dark reddish-brown with slightly lighter wings. The egg is pearly white and just visible to the naked eye. Larvae grow to about 1/8 inch long. They are legless grubs with glossy, reddish-brown heads and wrinkled, curved bodies. The pupa is delicate, white, and shaped somewhat like the adult.

Biology

pupa in galleryFound throughout North Carolina, southern pine beetles occur from Pennsylvania southwest to Arizona and south to Honduras. In its range, southern pine beetles breed in all species of yellow, white, red, and spruce pines, and in red and Norway spruce. Shortleaf, loblolly, Virginia, and pitch appear to be the preferred yellow pines.

pitch tubes in bark The southern pine beetle is one of the most destructive insect enemies of southern pines; it is especially damaging to stands of poor vigor. Outbreaks are often triggered by soil-moisture stresses and by man-caused disturbances. Southern pine beetles usually attack trees that are at least 15 years old. The first sign of an infestation is usually browning of tree crowns. First becoming yellowish, the needles turn brownish orange or light brown and in about 1-1/2 to 2 months are reddish-brown. Typically, pines are killed in groups ranging from a few trees to several hundred acres of trees.

gallery patternThe beetles often kill trees quickly by girdling them and by transmitting a blue stain fungus that plugs conductive tissues and degrades lumber.

Southern pine beetles become active in the spring about the time redbuds and dogwoods bloom. Either singly or in small groups, the insects first attack weakened and damaged pine trees; they may then spread over larger acreages. In pairs, the beetles invade the tree's main stem; during outbreaks, thousands of pairs may attack a single tree. They usually attack the middle and upper trunk first. Each pair constructs an S-shaped tunnel one foot long between the bark and wood. The tunnels crisscross to form an intricate pattern that girdles the tree. Eggs are deposited in niches along these tunnels. The larvae, usually feeding in the inner and outer bark, can be seen when the bark surface is whittled away with a hatchet. After a few weeks, the larvae change to pupae, and new adults emerge in a few more weeks.

The entire life cycle, under favorable conditions, takes from 30 to 40 days (three to five generations per year). The last brood of the season overwinters in various stages of development under or in the bark of infested trees. During certain periods, these insects may become so numerous that they are able to kill entire stands of trees up to several hundred acres.

Control

Control in coniferous evergreen shade trees - Regretably, little can be done and there are no real rescue treatments. Trees should be kept vigorous (by mulching and watering) and free from injuries and excessive grading around the roots or compaction of soil. Avoid competition with turf in root area. Cut infested trees down, debark and/or remove them immediately. Protective sprays for living trees are expensive and should only be considered for valueable specimen trees.
 

Pesticide  (Trade Name)  comments 
chlorpyrifos (DursbanPro) Not for residential areas
permethrin (Astro) & other  

bifenthrin

(Onyx)

 

For the most complete information, visit the USDA Forest Service Southern Pine Beetle information directory website at: Southern Pine Beetle . You may also visit the NC Forest Service link.


Recommendations of specific chemicals are based upon information on the manufacturer's label and performance in a limited number of trials. Because environmental conditions and methods of application by growers may vary widely, performance of the chemical will not always conform to the safety and pest control standards indicated by experimental data.

Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.

Other Resources

For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service.

Prepared by: James R. Baker & S. Bambara, Extension Entomologists


Published by North Carolina Cooperative Extension Service
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
© 2001 NC Cooperative Extension Service

ENT/ort-82 August 1994 (Revised) May 2001

Web page last reviewed January, 2011 by the webperson.