Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Early sowing offers the best protection for carrots - Carrot psyllids can destroy up to a third of a crop

22.01.2008
A doctoral dissertation produced at MTT Agrifood Research Finland reveals that early sowing of carrots is the most effective way to prevent the damage caused by carrot psyllids. If the carrot’s number one enemy gets at the seedlings at the cotyledon stage, it can rapidly destroy up to 35% of the crop.

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
Further information:
http://www.mtt.fi

More articles from Agricultural and Forestry Science:

nachricht Back to Nature: Palm oil plantations are being turned back into protected rainforest
21.03.2019 | Forschungsverbund Berlin e.V.

nachricht 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

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Unprecedented insight into two-dimensional magnets using diamond quantum sensors

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...

Im Focus: Full speed ahead for SmartEEs at Automotive Interiors Expo 2019

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...

Im Focus: Energy-saving new LED phosphor

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.

Im Focus: Quantum gas turns supersolid

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...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

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

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...
All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Hopkins researchers ID neurotransmitter that helps cancers progress

26.04.2019 | Life Sciences

Unprecedented insight into two-dimensional magnets using diamond quantum sensors

26.04.2019 | Physics and Astronomy

Liquid crystals in nanopores produce a surprisingly large negative pressure

26.04.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>