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 Alkaline soil, sensible sensor
03.08.2017 | American Society of Agronomy

nachricht New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>