Southern Pine Beetle Update

"As long as we have lots of loblolly pine, we'll have more frequent, more widespread, and more destructive southern pine beetle (SPB) outbreaks than our area has known in the past (when loblolly pine was much less common in Florida)." That view, stated by a Florida Division of Forestry (DOF) scientist, is shared by many researchers and practicing foresters familiar with the SPB. In northern Florida, in the last 25-40 years loblolly pine has colonized many old fields and pastures and had been widely planted for timber production.

In March, DOF Entomologists conducted a systematic SPB trapping program. Since 1986, this type of survey has been widely used throughout the south as a way to predict SPB activity. Predictions have proven to be accurate 75-85% of the time. In April, the prediction for northern Florida was that the heavy SPB outbreaks of the last two years would not occur in 1996. However, DOF did not drop it's guard and continued aerial surveys to pick up signs of any SPB outbreaks as early as possible.

So far this year, DOF's continuing surveillance has shown that forecast to be accurate ...with one major exception. There is now a rip-roaring southern pine beetle outbreak in southern Hamilton County, along the Suwannee River, with some "spots" in adjoining areas of Suwannee, Madison, and Columbia Counties. Timber company lands, State Forests, and non-industrial private holdings have all been affected. Dense plantations as well as older natural stands are involved. The severity of this outbreak is attributed to the vast amount of preferred host material--loblolly pine--that is available. In this particular infestation the attacks have not yet involved slash, longleaf or other pines besides loblolly.

To try to stop the spread of the beetles (and to salvage the wood of the dead and dying trees), the owners have loggers "cutting like crazy" in and around the Hamilton Co. infestations. We hope everyone is following the correct precautions for handling this wood: The mill should be informed in advance that infested wood is coming in. Once at the mill, the wood and bark of the infested trees should be processed immediately, killing all SPB eggs, larvae, pupae, and adults present.

Hurricanes and SPB outbreaks have taught the state government that it is sometimes unwise to follow all the standard rules for cutting trees on State lands. To get infested and at-risk trees rapidly removed and bring SPB outbreaks under control, a new "fast track procedure" is now being followed on affected Water Management District and State Forest lands. This arrangement seems to be working well this year; loggers start work in the woods only about three weeks after an SPB infestation is first spotted on State lands.

So far, in this year's Hamilton Co. outbreak no premerchantable stands have been attacked. However, 1995 infestations included some five year old stands on company lands. The company bulldozed the infested areas and buffers around them. This worked pretty well. With the tree trunks lying exposed in the sun, heat killed most of the beetles in them. Also, this procedure disrupted the chemical communications that the insects use to attack trees in overwhelming numbers; the beetles that did emerge from the felled trees did not start new outbreaks.

SPBs are present in other areas of north Florida this year, but, with the help of other kinds of bark beetles, they are mainly just taking out scattered trees that have been weakened or wounded by lightning or other factors. They are not attacking nearby healthy trees. That is how SPBs almost always operated before changes in land use provided them with vast, dense natural stands and plantations of their preferred host, loblolly pine.

The first easily noticed sign of an SPB outbreak in your woods is a group --a half dozen trees or more--of dying pines (trees with mostly yellowing or red needles). This would be most likely to occur in a loblolly stand. However, when an outbreak gets going, other pines, even longleaf, may be attacked. In an SPB infestation, the dying trees will usually have many popcorn size "pitch tubes," up and down the trunk, where sap has oozed out of the holes where the beetles bored in. If the victim trees were highly stressed before the beetle attack, pitch tubes may not be present, but reddish dust from the beetles' boring through the bark may be seen around the tree on spider webs, leaves, and cracks in the bark. Peel some loose bark from a dead tree. Winding , S-shaped galleries (made by the tunneling adult beetles) on the inside of the loose bark are a telltale sign of SPBs. In the kind of SPB presence that is cause for alarm, the beetles attack healthy looking green pines near the dying ones. Pitch tubes 10-20 feet up the trunk are the first sign of the attack on green trees. As more beetles attack the tree, more pitch tubes appear higher and lower on the trunk.

If you come across what looks like an active SPB infestation in your woods, contact a knowledgeable forester. If it is indeed a spreading SPB "spot", try to contain the damage: with the forester's guidance, bring in loggers to take out the infested and at-risk trees. In Florida today, 95% or more of the reported SPB "spots" are first noticed during aerial surveys.

For more information about the Southern Pine Beetle, contact your local Cooperative Extension Service office or County Forester.