Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UGA study offers hope for hemlock attack

11.01.2012
Thousands of broken trees line the banks of the Chattooga River. The dead gray stabs were once evergreen monsters offering shade to trout and picturesque views to visitors. These Eastern hemlocks are dying rapidly, and University of Georgia researchers are working to save them.

One tiny insect, the hemlock woolly adelgid, is to blame. The Asian insect first appeared in the eastern U.S. in Richmond, Va., in the 1950s. In 2003, it crossed the river from South Carolina and started feeding on Georgia trees.

The tiny pests suck up cells from the tree's needles, which prevent them from transferring water and conducting photosynthesis. The first obvious sign of an infestation is thinning foliage. Needles fall off, and the crown starts thinning. From a distance, trees look gray.

Researchers working to find ways to combat the adelgid have focused on releasing ladybird beetles, which eat adelgids. A new UGA study brings some of the logistical issues to light and offers hope for more successful control in the future. The results were published in the December issue of the Journal of Economic Entomology.

"Because the trees being attacked live mostly in remote forests where insecticide application is impractical, predators may be the best hope for tree survival," said Shimat Joseph, former UGA doctoral student who authored the journal article.

Previous studies have shown widely released predator beetles, Laricobius nigrinus and Sasajiscymnus tsugae, have been successful in controlling hemlock wooly adelgid populations, but they have not survived well through multiple seasons.

"Adelgid populations are not concentrated where we are releasing the predators," Joseph said. "Previous studies assumed populations are evenly distributed, but we are seeing that is not the case."

According to the study, adelgid populations tend to be more abundant in the upper crown, especially early in the infestation. This study suggests predator releases should focus in this area where higher densities are more likely. Up to this point, releases have been made in the lower third of the tree crown.

"Chemical control can slow the spread of adelgids, but beetles provide some hope that we will be able to manage the adelgids and bring them into balance. We may never be able to eliminate them," said Kris Braman, an entomologist with the UGA College of Agricultural and Environmental Sciences and co-author of the paper.

The three-year study looked at the population rates of adelgids in hemlocks located in the Chattahoochee National Forest. The 60 north Georgia trees selected for the study were 25 to 70 years old.

Predator beetles are reared on infested hemlock branches in labs. When released, the branches, saturated with about 100 beetles, are tied to living trees where populations have been identified. Strategic placement of the predators is important for successful control of the adelgid-and for the bottom line.

"Because the beetles are so expensive to grow, every single little beetle is like releasing diamonds over the canopy," Braman said.

A cocktail of fertilizer and insecticide was applied to the trees included in the study to develop an application ratio that would maintain tree health while keeping enough adelgids alive to serve as sustainable food for the beetles but not enough to kill the tree.

"Part of the problem with maintaining predator beetles has to do with the declining tree health," said study co-author Jim Hanula, an entomologist with the U.S. Forest Service and adjunct faculty in the UGA department of entomology. "As tree health declines, adelgids produce fewer eggs and, in turn, less food for the predators."

Georgia trees decline faster than those found in northern states due to a lack of winter weather, which kills back adelgid populations in the North.

The full article is available online at http://www.bioone.org/doi/full/10.1603/EC11022

Kris Braman | EurekAlert!
Further information:
http://www.uga.edu
http://news.uga.edu/releases/article/uga-study-offers-hope-for-hemlock-attack/

More articles from Ecology, The Environment and Conservation:

nachricht Emissions from road construction could be halved using today’s technology
18.05.2020 | Schwedischer Forschungsrat - The Swedish Research Council

nachricht When every particle counts: IOW develops comprehensive guidelines for microplastic extraction from environmental samples
11.05.2020 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

German-British Research project for even more climate protection in the rail industry

28.05.2020 | Transportation and Logistics

A special elemental magic

28.05.2020 | Physics and Astronomy

Skoltech scientists get a sneak peek of a key process in battery 'life'

28.05.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>