Dave Leatherman told a group of about 20 interested Kimball County residents more about pine beetles than they dreamed could be known.

Leatherman is a natural resource consultant who has spent a lifetime studying the pine beetle. He had been associated with Colorado State University for 33 years and has done work in the Panhandle annually since 1984.

He is very familiar with the massive invasion of Colorado’s mountain forests by  pine beetles.

He is quick to point out that the recent Nebraska infestation has caused him to doubt what he thought was the absolute truth about pine beetles.

Leatherman said that the enormous Colorado devastation caused by the pine beetle has occurred at mountain elevations in areas of generally cold winters.

He said the advance of the beetles is generally from infested tree, flying to a green tree a short distance away.

The Nebraska beetle invasion ranges from Scottsbluff to Sidney and possibly as far east as Alliance.

Leatherman said he thinks the beetles were lifted into the atmosphere from their Colorado mountain home and blown northeastward by strong winds. This probably happened in August 2008.

Leatherman inquired of the Federal laboratories and agencies in Boulder, Colorado if such wind conditions had existed, but got no helpful information.

Once in Nebraska, the beetles took on new life cycles that baffled Leatherman at first. The beetles were reproducing too fast.

This was because the winter temperatures are much warmer than the beetles previous habitat in the Colorado mountains.

Leatherman stressed several times that the beetles prefer to attack Scotch Pine trees.

He told how the female beetles attack the trees, boring through the bark to get into the space between bark and tree trunk.

The females then emit a characteristic pheromone which attracts the male beetle. The males must emit the right chirping noise for the female to quit blocking the entrance to the bore tunnel and let the male enter the space between the bark.

There they fall in love and mate.

The female digs a groove under the bark but on the surface of the tree trunk. She lays a lot of eggs at various locations along the tunnel. The eggs hatch and the larvae turn into pupae and then finally into adult insects which exit the tree the following July or August to move on to another tree.

That was the normal life cycle.

Leatherman says the life cycle seems to be accelerated in the Panhandle because of the warmer weather.

He said the adult beetles had formed and some emerged from the tree in late fall, instead of the normal “next July or August.” These beetles likely freeze to death.

The adult beetles that stayed under the bark were too adult to manufacture the glycol that keeps the pupae from freezing during mountain winters. These guys likely froze because they lacked the glycol antifreeze.

Leatherman said words to the effect that, “This beetle problem may be short lived because so many prematurely adult beetles died during the winter.”

Of course, the Scotch Pine trees resisted the beetles attack. The trees attempt to expell the boring beetle by flooding the bore hole with tree fluids. The evidence of this defense is white pitch tubes on the tree bark. The material sort of resembles fluffy white popcorn.

Leatherman says it takes about 1,500 beetle bore holes to kill a tree. Trees hit by 500 to 700 beeetles have a strong chance of survival.

The tree will be effectively killed in three days if hit by 1,500 beetles.The many bore holes effectively cut off the water supply.

“Trees that have pitch tubes every three or four inches all around the tree upwards to where the trunk is six inches in diameter are not going to make it,” said Leatherman.

It may take nine months for the tree crown to turn red, showing visible proof of the death of the tree.

Leatherman said, “Most of the trees attacked around the golf course will survive.  Maybe 10 or 20 trees have lost the battle with the beetles.”

The wood of trees infested by the beetles still has excellent commercial use as studding and siding. It tends to be a little softer so it should not be used for flooring.

The wood of infested trees takes on a blueish tint which is rather attractive and lends itself to unique interior paneling works.

Cold weather in an enemy of the beetle but three days of -30 to -40 degrees F. are required to kill the larvae.

Woodpeckers are also an enemy of the beetles. Unfortunately, woodpeckers are loners and don’t congregate in flocks.

Leatherman humorously asked, “Did you ever see a flock of woodpeckers.”

He concluded by saying that the logs of dead infested trees can be treated with diesel oil to kill the larvae. Baking the logs (wrapped in clear plastic) in summer sunlight for several weeks also works.

Live trees can be sprayed to prevent beetle attack in the first place. Forested areas can be thinned to allow the surviving trees to regain tree health.

At this point, Tom Wein continued the presentation. He said beetles are not the problem, sick trees are the problem.

Wein made the point that pine beetles only attack sick trees. He holds the opinion that sick trees emit a negative charge which attracts  the beetles.

Wein said that diverse plantings of excellent nursery stock are the best way to have healthy stands of trees.

He said having many varieties of trees prevents one species of insects from wiping out their favorite food tree.

Overplanting of Scotch Pines gives the pine beetle a banquet area of their favorite food. Diversity of tree varieties would prevent this.

Wein showed examples of nursery- stock trees that were “root-bound” and not capable of growing to be healthy trees. These are prime targets for insects like the pine beetle.

He also said proper soil conditions are essential to good tree health.

Wein told how the forest floor was covered with leaves, twigs and bark. These materials become excellent feed for trees when worked into the soil.

Adequate spacing is also necessary for good tree health.

And water is important.

Wein said that the Panhandle drought with only 12 inches of natural moisture causes near-desert conditions. Deep watering is essential, especially in the fall months.

Leatherman and Wein took numerous questions from the audience and passed on much valuable information.

Wein performs many types of tree services. He lives in Bayard and can be reached at 308-631-4315.