Have you ever heard the term, “research and development”? You may know that research is a systematic process scientists use to solve problems, answer questions, and discover new knowledge. Development happens when the new knowledge is used to create new technology. The new technology could involve a process, product, or both.

The research and development process is often cyclical. Scientists do research and develop new technologies based on new knowledge. The new technology is further tested in an additional laboratory or field research project. The testing provides information to scientists about the success of the new technology. The testing might also suggest a need for more research and development.

The scientists in this study wanted to test a new technology. The new technology may protect pine trees from a beetle that damages or kills the trees (see below for more information). In this study, Forest Service scientists worked with a scientist from a company to develop the technology. By working together, the scientists could determine whether the new technology could protect pine trees.

Mountain pine beetles are found across western North America (figure 1). Mountain pine beetles lay eggs in the boles, or trunks, of pine trees that grow in the mountainous West (figure 2). Mountain pine beetles live most of their lives under the bark of pine trees. New adult beetles emerge from a pine tree and seek a new pine tree in which to mate and lay eggs. When a beetle finds a pine tree, scientists say that the beetle has attacked the tree.

To complete their reproductive cycle, mountain pine beetles tunnel beneath the bark. This tunneling disrupts the flow of nutrients moving from the needles to the roots. The beetles also carry a fungus to the tree. This fungus helps to stop the movement of water from the tree’s roots to its needles. When the flow of nutrients and water is fully disrupted, the tree will die.

Under normal circumstances, mountain pine beetles are a natural part of western forests. Recent changes in climate and forest conditions, however, have increased mountain pine beetle attacks. When more pine beetles attack the trees, more trees are killed. When many pine trees are killed, other problems can occur. For example, water quality and wildlife habitat are reduced, and biodiversity and carbon storage are affected.

In recent years, mountain pine beetles have killed so many pine trees that the western mountain forest ecosystem is changing. Western forests, with so many dead pine trees, are now in danger from large uncontrolled wildfires. Animals that depend upon larger pine trees have less habitat. The scientists in this study, therefore, were interested in testing a new method to protect pine trees from mountain pine beetle attacks.

Mountain pine beetles are killing many pine trees in the Western United States (figure 3). When many pine trees die, the forest ecosystem changes and the chance for wildfires increases. Scientists and forest managers, therefore, want to protect as many pine trees as possible. Scientists use pheromones as one way to protect pine trees.

Pheromones are chemicals released by plant and animal species to communicate with members of their own species. Mountain pine beetles have an interesting way of using pheromones to help them successfully reproduce in pine trees (see Thinking About Science above).

Scientists can create artificial pheromones in the laboratory. Mountain pine beetles cannot distinguish these laboratory-produced chemicals from the pheromones produced by other beetles. Some of these chemicals repel beetles from an area. A repellent chemical, therefore, can be used to repel beetles from attacking pine trees.

One of these repellent chemicals is called verbenone. Verbenone is produced when pines decay, as the beetles eat, and in the beetle tunnels. To successfully protect a tree, verbenone must stay effective while adult beetles emerge from pine trees to find new trees.

In lodgepole pine (Pinus contorta) forests, where much of the damage has occurred, the beetles fly to and attack new trees. Beetles attack most often in July and August. They may also attack in June and September.

The scientists in this study were interested in testing a new way to use verbenone to protect pine trees. A company called ISCA Technologies, Incorporated, worked with the Forest Service to develop a new technology. This technology was Specialized Pheromone and Lure Application Technology, or SPLAT. The scientists included verbenone in the mixture and called this technology SPLAT Verb. The pheromones in SPLAT Verb are mixed into a waxy substance so they can be applied to pine tree boles.

The scientists wanted to answer the following questions: (1) How well does SPLAT Verb protect individual lodgepole pine trees, and areas of pine trees, from mountain pine beetle attack? and (2) How long does the protection last?

The scientists wanted to test how well SPLAT Verb protected individual lodgepole pine trees and an area around them from mountain pine beetles. Lodgepole pine is a two-needled pine found throughout much of Western North America (figure 4). The study was conducted on the Bridger-Teton National Forest in 2012 and 2013 (figures 5 and 6).

First, the scientists found an area with mountain pine beetle damage. In this area, the beetles had killed about 12 percent of the lodgepole pine over the previous 2 years (figure 7).

The scientists randomly selected 60 live trees to study. The trees were separated from each other by at least 100 meters. On June 19, 2012, the scientists stapled a substance on the north side of the trunk of each of the 60 trees in the study. This substance was a bait containing pheromones, which was intended to attract mountain pine beetles to each tree.

Half of the trees were given SPLAT Verb. Trees treated with SPLAT Verb were called the experimental treatment. The other trees were called the control. In the control treatment, the scientists identified and observed the trees but did nothing to them, besides stapling the bait to the trees.

On the same day they applied the bait, each tree in the experimental treatment was treated with 70 grams of SPLAT Verb. To make SPLAT Verb, the verbenone was mixed with a waxy substance. The wax enabled the verbenone to stay on the tree’s trunk. This special way to apply verbenone was the technology called Specialized Pheromone and Lure Application Technology-Verbenone, or SPLAT Verb.

The SPLAT Verb was applied to each tree in four 17.5-gram dollops. Each dollop was put on the tree trunk using a caulking gun (figure 8). A dollop was put on the tree 2.5 meters above the ground in each of the four directions – north, south, east, and west.

On October 9 and 10, 2012, each of the trees in the study was observed for signs of mountain pine beetle attack. Additionally, all trees within an 11-meter radius of each treated and control tree were observed for mountain pine beetle attacks (figure 9).

Using their observations, the scientists placed each tree’s condition into one of four categories, according to the amount of mountain pine beetle damage they observed (figure 10). The categories were:

1. no attack,
2. an unsuccessful attack,
3. a strip attack (an attack of part of a tree’s trunk, but one that does not extend around the tree’s circumference; a strip attack will usually not kill a tree), or
4. a mass attack (occurs when bark beetles attack all the way around the tree trunk; a mass attack is so large that it overcomes all of the tree’s defenses and almost always kills a tree).

The scientists waited until June 21 and 22, 2013, to observe the trees again. A tree was judged to be alive if no “crown fade” was visible and judged to be dead if “crown fade” was visible. Crown fade is a discoloration of the tree’s needles from green to yellow to red.

Next, the scientists needed to answer their second question. This question was, “How long does the protection provided by SPLAT Verb last?” To answer this question, the scientists placed dollops of SPLAT Verb on trees in a forest in Riverside, California. On days 1, 10, and 30, scientists randomly removed five dollops for laboratory analysis. They determined the amount of verbenone left in the SPLAT Verb dollops through chemical analysis.

Every lodgepole pine tree in the control group was attacked by mountain pine beetles and more than 93 percent died. All the lodgepole pine trees treated with SPLAT Verb were protected from mountain pine beetles (figure 11).

Recall that the scientists also observed trees within an 11-meter radius of the individual trees. The scientists found that SPLAT Verb protected trees beyond the individual tree that received the chemical treatment (figure 12).

The scientists also tested how much of the verbenone in SPLAT Verb was released over 30 days. To be effective, the SPLAT Verb had to release verbenone long enough to repel beetles over the weeks adult beetles were flying and searching for trees to attack.

The average release of verbenone during days 10 through 30 was 14.7 milligrams per day. If this average release rate continued past the 30 days, the amount of verbenone in a dollop would last an additional 75 days before it would be gone.

The scientists tested a technology aimed at reducing the damage done to lodgepole pines by mountain pine beetles. To protect individual lodgepole pine trees from mountain pine beetle attacks, the scientists made a recommendation. The scientists recommended applying four dollops, each containing 17.5 grams of SPLAT Verb, to the tree at the beginning of the beetles’ flight period.

The scientists also recommended doing additional research. First, they recommended testing the use of less SPLAT Verb. They also recommended two more studies: one on how SPLAT Verb can protect larger areas of lodgepole pine trees from mountain pine beetles, and another on whether SPLAT Verb can protect other pine tree species from mountain pine beetles.