|University of Kentucky Entomology|
SOUTHERN PINE BEETLE
by Lee Townsend, Extension Entomologist, and Lynne Rieske-Kinney, Research Entomologist
University of Kentucky Department of Entomology
Southern pine beetles are 1/8 inch long and have cylindrical, reddish-brown to black bodies. There are several overlapping generations in Kentucky each year. All stages of the life cycle (egg, larva, pupa, and adult) can be found in trees at any time. Development is faster in the summer (26 days) than during the winter (54 days). Following a period of relative inactivity in the winter, adults begin to fly again in the spring.
Larvae chew curved or S-shaped galleries under the bark in the inner bark and cambium layer, and can girdle and kill the tree. In addition, the beetles introduce a fungus that can be lethal to the tree. Other species of bark beetles can be present in the same tree but their larvae produce I-, Y-, or H-shaped galleries (See Entfact 437, Borers That Attack Landscape Pines).
During outbreaks, they attack trees that appear to be healthy and vigorous. Infestations usually begin on the mid-trunk area and then expand up and down the length of the tree. Resistant species such as slash, longleaf, and eastern white pine, have a high resin exudate that provides an effective defensive mechanism against the beetle.
However, even resistant trees can be attacked successfully when the beetles are very abundant.
Management of Infestations
Southern pine beetles often attack stressed and injured trees in older-aged, dense stands, so cultural practices that promote healthy trees will reduce the frequency and severity of infestations. During outbreaks, avoid pruning and other activities which produce odors that attract dispersing beetles.
An insecticide may be sprayed onto the trunk of landscape pines to protect them when there is an active SPB infestation in the area. Products labeled for bark beetle control include Astro (permethrin), Dursban (chlorpyrifos), or lindane. Dursban is being withdrawn from the market place but existing products can be used according to label directions. The insecticide should be applied on dry bark to the point of runoff, from the base of the crown down to the ground. This is a preventive approach only, since the insecticide will not penetrate the bark and kill life stages that are already in an infested tree. Several applications (spring, mid summer, and late summer) may be necessary because of the long activity period of the adults. When carefully and properly applied, these insecticides dry in a few hours and pose little danger to birds, squirrels, or humans.
Since SPB attack mature trees, spray coverage and potential applicator exposure can be a problem. Relatively high pressure, provided by specialized equipment, may be needed to spray the trunk to an adequate height. Consider using a certified commercial applicator.
Southern pine beetles have natural enemies that can have a significant impact on their mortality over a wide area, but will probably not provide satisfactory protection of individual or small numbers of trees in a landscape setting.
Short Term Strategy
Long Term Strategy
CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.
Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!
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