In her dissertation, Research Scientist Anne Nissinen examined ecological methods of fighting carrot psyllids. The study was conducted in a greenhouse where the pests were allowed to feed and lay eggs on 15 different carrot varieties and a wild carrot in cages.
Nissinen examined the carrot psyllid host plant selection and the severity of the damage caused by the pest at different stages of root and shoot growth. She also assessed the possibility to utilize the push-pull strategy in management carrot psyllids.
Small, Ugly And Bearded Carrots
Carrot psyllids are a major problem in Finland’s most important carrot production regions. The psyllids overwinter in spruce trees and fly to carrot fields from early June onwards. They instantly begin to suck nutrients from carrot leaves, which quickly renders the shoots damaged.
Carrot psyllid attacks usually peak either a week before or a week after the summer solstice. In terms of the crop, it is critical that the shoots have grown enough by that time to survive the pest attack.
If the carrots have only been sown in the end of May, the pests may catch the shoots at the cotyledon stage when the carrots are most vulnerable to damage. After a pesticide treatments, the shoots may recover and look fine on the surface, but reveal small, ugly and bearded carrots at harvest, Nissinen describes.
More Research Needed Into Lure Plants
Nissinen also examined whether a particular carrot variety was more attractive to psyllids than others, which would allow it to be used as a trap crop to keep the pests from attacking the cultivated variety. Of the varieties studied, an old non-hybrid variety, which can still be found on a Swedish seed list, turned out to be the most attractive.
Nissinen believes that the use of a trap crop could be an efficient way of reducing the numbers of psyllids on carrot crops. She does, however, concede that she dare not recommend the use of trap crop in practice based on this study alone.
The effectiveness of a trap crop should always be tested in comparison to the cultivated variety in question, Nissinen concludes.
Psyllids Unfazed By “Bad Smell”
The study also included an experiment where carrot psyllids were exposed to a volatile compound: limonene. Limonene can be found both in carrots and in the psyllids’ winter host, the spruce.
A study conducted in Sweden during the last decade found that limonene repelled carrot psyllids in the field. In Nissinen’s greenhouse experiments, however, limonene failed to shoo psyllids away. neither when sprayed directly onto the carrot crop nor when released from a carrier substance.
The contradiction between the research findings may be because greenhouse conditions differ from field conditions and the psyllids are unable to carry out the change of host plant as they would in the course of their normal live cycle. Nissinen explains.
She adds that in her opinion it is important that future experiments involving potential repellents or attractants should take place in field conditions.
The dissertation of Anne Nissinen, M.Sc. (Agriculture and Forestry), is in the field of environmental science and is titled “Towards ecological control of carrot psyllid (Trioza apicalis)”. The dissertation will be reviewed on 25 January 2008 at the University of Kuopio, Finland. Nissinen’s opponent will be Doctor Robert Glinwood from the Swedish University of Agricultural Sciences, and Professor Jarmo Holopainen from the University of Kuopio will be acting as her supervisor.
Ulla Jauhiainen | alfa
Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli
26.04.2017 | University of the Basque Country
New data unearths pesticide peril in beehives
21.04.2017 | Cornell University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences