Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Coconut palms in the Comoros are now protected by a parasitoid

08.01.2008
Aleurotrachelus atratus Hempel is a whitefly that has been attacking coconut palms in the Comoros since 2000. According to the islands' Ministry of Agriculture, it has resulted in a 55% drop in coconut yields on three islands: Nzwani, Mwali and Ngazidja, the latter being by far the worst affected.

The insect attacks the fronds and feeds on the palms' sap, excreting a honeydew on which sooty mould fungi develop. This is what causes the blackish colouring seen on the upper side of the fronds on affected palms. The whitefly is a curse for these islands covered in coconut palms, whose nuts play a vital role in Comoran society.

Until now, there has not been any way of controlling whiteflies in the Comoros. A specific research programme, aimed at identifying and introducing a biological control agent in the region, was launched in 2005 by CIRAD and the Agriculture, Fisheries and Environment Research Institute (INRAPE) in the Comoros*. The programme has just been completed.

Over two years, the researchers met their target: they identified a parasitoid in Réunion that was specific to the coconut whiteflies found in the Comoros. It is a species of Eretmocerus whose taxonomy is currently being described.

Within eight months, whitefly larva densities were cut by between 12 and 73%, depending on the island

After checking that Eretmocerus nr sp. preserved other whitefly species that might be found in the Comoros, notably endemic species, the first parasitoids were released in early 2007 on Ngazidja. Three hundred females collected in Réunion were introduced in a confinement cage, placed on a highly infested coconut palm around two metres tall. The female parasitoids are attracted by their host and lay their eggs under whitefly larvae on the fronds of coconut palms. As they hatch, the parasitoid larvae pierce the testa of the whitefly larvae and eat them from the inside, leaving just an empty mummy behind.

Eight months after the releases, the researchers checked that the Eretmocerus nr sp. had acclimatized to these semi-natural conditions, via the experimental cage on Ngazidja, and to natural conditions on Nzwani. The phytosanitary condition of the coconut groves in the Comoros had improved significantly: whitefly larva densities had been cut by 12% on Ngazidja, 62.5% on Nzwani and 73% on Mwali. Production had increased, which resulted in a drop in coconut prices, to the benefit of consumers.

The main objective set for the programme, viz. to bring whitefly population levels below a harmfulness threshold using a natural parasitoid, was thus achieved. However, the "whitefly-parasitoid" balance needs to be monitored for the first few years after acclimatization, to confirm the success of the operation and measure the increase in coconut palm growth and coconut production on the three islands.

* The biological control programme was conducted within the Crop Protection Network for the Indian Ocean (PRPV).

Helen Burford | alfa
Further information:
http://www.cirad.fr/en/actualite/communique.php?id=849

More articles from Agricultural and Forestry Science:

nachricht How much drought can a forest take?
20.01.2017 | University of California - Davis

nachricht Plasma-zapping process could yield trans fat-free soybean oil product
02.12.2016 | Purdue University

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>