Findings from the U.S. Forest Service-funded study appear in the February issue of Forest Ecology and Management. The study was conducted in California and Idaho, and showed how applications of laminated flakes containing a substance called verbenone resulted in a three-fold reduction in insect attack rates, compared to areas where they were not applied.
The technique could provide a way to treat infestations on a large scale and limit further spread into millions of acres of trees made vulnerable because of climate change, overcrowding and fires.
It could also be an alternative to insecticides, which can have adverse environmental effects. Thinning of some overstocked forests is still recommended to reduce susceptibility to bark beetles. But, the flakes can provide some protection for the dense, old-growth stands required by wildlife, according to the scientists.
The largest beetle outbreak in North American history is now occurring in Canada, where more than 22 million acres are affected, according to the British Columbia Ministry of Forests and Range. Outbreaks of this magnitude exacerbate global warming by converting forests from carbon sinks to carbon sources.
Scientists have known for more than a decade that one of the safest strategies for deterring such infestations was through application of verbenone, which beetles release to inhibit aggregation by members of their own species, and the Food and Drug Administration has approved for use as a flavor ingredient. But, manual application of verbenone is difficult where infestations cover thousands of acres in remote, steep terrain.
"Verbenone flakes gave significant protection from mountain pine beetles when applied to low to moderate beetle populations," said Nancy Gillette, a Forest Service scientist at the Pacific Southwest Research Station and one of nine researchers involved in the study. "Higher beetle populations will probably require higher application rates."
Gillette and her colleagues speculated that flakes released from the air might better disperse and simulate natural beetle release than large, manually-applied verbenone packets so they used helicopters to release flakes.
They treated 10 plots at two sites, one near Mount Shasta in Northern California and another in Idaho's Bitterroot Mountains. The sites had similar tree densities and existing rates of infestations. Helicopters dropped flakes on half of the plots and left the others untreated, with application rates of about 9.7 flakes per square meter.
The treatments reduced the level of attack to about a third of that in untreated plots in both California and Idaho. Future studies will test a biodegradable formulation of the flakes.
The study, "Aerially Applied Verbenone-Releasing Laminated Flakes Protect Pinus Contorta Stands From Attack by Dendroctonus Ponderosae in California and Idaho" can be seen in the journal Forest Ecology and Management at: http://dx.doi.org/10.1016/j.foreco.2008.12.017
Kakao in Monokultur verträgt Trockenheit besser als Kakao in Mischsystemen
18.09.2017 | Georg-August-Universität Göttingen
Ultrasound sensors make forage harvesters more reliable
28.08.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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