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
Back to Nature: Palm oil plantations are being turned back into protected rainforest
21.03.2019 | Forschungsverbund Berlin e.V.
The inner struggle of the evening primrose: Chloroplasts are caught up in an evolutionary arms race
14.03.2019 | Max-Planck-Institut für Molekulare Pflanzenphysiologie
For the first time, physicists at the University of Basel have succeeded in measuring the magnetic properties of atomically thin van der Waals materials on the nanoscale. They used diamond quantum sensors to determine the strength of the magnetization of individual atomic layers of the material chromium triiodide. In addition, they found a long-sought explanation for the unusual magnetic properties of the material. The journal Science has published the findings.
The use of atomically thin, two-dimensional van der Waals materials promises innovations in numerous fields in science and technology. Scientists around the...
Flexible, organic and printed electronics conquer everyday life. The forecasts for growth promise increasing markets and opportunities for the industry. In Europe, top institutions and companies are engaged in research and further development of these technologies for tomorrow's markets and applications. However, access by SMEs is difficult. The European project SmartEEs - Smart Emerging Electronics Servicing works on the establishment of a European innovation network, which supports both the access to competences as well as the support of the enterprises with the assumption of innovations and the progress up to the commercialization.
It surrounds us and almost unconsciously accompanies us through everyday life - printed electronics. It starts with smart labels or RFID tags in clothing, we...
The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.
Light emitting diodes or LEDs are only able to produce light of a certain colour. However, white light can be created using different colour mixing processes.
Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.
Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...
A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter
17.04.2019 | Event News
15.04.2019 | Event News
09.04.2019 | Event News
26.04.2019 | Life Sciences
26.04.2019 | Physics and Astronomy
26.04.2019 | Physics and Astronomy