What's the status of the biodiversity in differently managed triticale fields? This is what the biologists at the Department of Animal Ecology & Tropical Biology wanted to find out. Triticale is a cross between wheat and rye. The cultivation of this crop is on the rise across the globe, because it delivers good yields even in poor soil conditions.
When comparing conventionally managed crop fields, which were either sprayed with insecticides or were left untreated, Jochen Krauss, Iris Gallenberger and Ingolf Steffan-Dewenter made a discovery, which should catch the attention of every farmer: "According to our results, the preventative application of insecticides against aphids does not produce any advantages even though it consumes a lot of time and money," Jochen Krauss sums up.
The scientists studied five triticale fields that were sprayed with insecticides against aphids, comparing them to ten other fields without any such treatment. "To be sure, the application of the insecticide led to a short-term decrease of the pest density," says Krauss. "After four week's time, however, significantly more aphids could be found in these fields than in insecticide-free fields. This also astonished the farmers who made their fields available for our study."
More aphids as a result of a decrease in natural enemies
The scientists offer two possible explanations for this phenomenon. One possibility is: The insecticides indiscriminately kill off beneficial animals that feed on the aphids, such as ladybugs or the larvae of lacewings and hoverflies. Because their enemies are missing, the aphids find it easier to return and proliferate than in insecticide-free fields.
Another possibility is an indirect effect: The insecticide just kills the aphids, after which their enemies leave the field for a lack of prey. Final result: In this scenario, the aphid population can also recover better after their return because the natural enemies are missing.
Greater biodiversity in organic crop fields
In conventional fields that have not been sprayed with insecticides, the pest control through natural enemies seems to work better – thanks to the higher biodiversity in these fields. The biodiversity is far greater still in fields under organic management, as reported in PLoS One by the Würzburg scientists.
The researchers found five times as many plant species and 20 times more types of pollinating insects in the 15 organic crop fields included in the study than they did in conventional fields. Furthermore, they detected three times as many natural enemies of aphids and five times fewer aphids in the organic fields than in the conventional fields.
"Decreased functional diversity and biological pest control in conventional compared to organic crop fields", Jochen Krauss, Iris Gallenberger und Ingolf Steffan-Dewenter, PloS One, 18 May 2011
PD Dr. Jochen Krauss, Department of Animal Ecology & Tropical Biology at the University of Würzburg, T (0931) 31-82382, firstname.lastname@example.org
Climate change, population growth may lead to open ocean aquaculture
05.10.2017 | Oregon State University
New machine evaluates soybean at harvest for quality
04.10.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Life Sciences
17.10.2017 | Physics and Astronomy
17.10.2017 | Life Sciences