African wasps let loose in LOS to save cavassa

[Spitfire]

African wasps let loose to save cassava
Published: 18/07/2010 at 01:56 AM
Online news: Local News


Agricultural scientists have unleashed an insect in a bid to save northeast Thailand's cassava plants from an infestation that could cut the harvest from the billion dollar industry in half.

The team on Saturday released 10,000 wasps in Khon Kaen province to prey on mealybugs, said Rod Lefroy, a researcher for the Consultative Group on International Agricultural Research.

If the trial goes well, another 250,000 will be set loose.

Cultivated by five million Southeast Asian farmers, cassava is used in biofuel and livestock feed, and its starch is extracted for use in food. Thai exports of the crop account for more than 60% of global totals and generate about 48.3 billion baht (US$1.5 billion) for local farmers annually, the group and its research partners said.

The crop, originally brought from South America by Portuguese traders centuries ago, thrived before the mealybug infestation, which has spread to 200,000 hectares in Thailand's north and northeast and could cut yields by up to 50%, leading to millions in lost revenue, they wrote in a statement.

The mealybug, Phenacoccus manihoti, sucks the sap of cassava until it is dry and shrivels up. CGIAR, whose regional headquarters is in Laos, initiated the Anagyrus lopezi wasp project after Thai farmers noticed bugs clinging to withered cassava plants in large numbers last year, when crop production decreased by 20% to 30%, Mr Lefroy said.

"Although they are very small, they tend to amass in quite large numbers on the underside of leaves," said Mr Lefroy, who is working with the Colombia-based International Centre for Tropical Agriculture, the Benin-based International Institute of Tropical Agriculture and Thailand's Agriculture Ministry.

"They're very white and look like they're covered in a silky fur," he said.

After confirming the identity of the invasive bug, the team in Thailand imported the biocontrol wasps from Benin in Africa, and began a massive breeding and testing programme to prepare for Saturday's release. In the 1980s, wasps were successfully used in Africa to eradicate mealybugs preying on cassava.

The female wasps, only 2mm long, inject their eggs into the mealybugs and feed on them, gradually reducing their population.

Mr Lefroy said it is increasingly a regional problem and until recently Asia was largely exempt from the mealybug problem.

"We really need to move into a phase where we admit the honeymoon is over," he said. (Agencies)

Source - BBC News

Comments - Well, all sounds good from the official source, but we have to ask about the meddling factor there, might work or not but these decisions shouldn't be lightly taken, hope they are not swapping one problem for another.

Hmmm.............

[STEVE G]

We've got a lot of cassava around our place in Nong Ki and grew some ourselves for a couple of seasons but we never had a problem with the mealy bugs then.
I'll have a look when I'm up there in a month or two, for bugs or wasps.
I've got no problem with wasps as long as they find mealy bugs more attractive than the neck of my bottle of Chang!

[Takiap]

They can drop off a few of those wasps here in Borfai if they want. I'm bloody sick to death of mealy bugs. Almost anything I try and grow, such as fruits and/or veg, and the mealy buggers are at it. It's always worse during the dry season, and all those stupid "herbal & natural" sprays don't work, no matter what the bottles say. I hate using chemicals, so I've basically given up trying to grow anything for the table. I know, silly me because all the fruit and veg you buy has been drenched in chemicals as it is.

Ah well, at least those bugs are leaving my corn, chillies, pak boong, tang thai, and pak choy alone Oh yes, they're also not interested in chicken eggs, so at least I still get breakfast when the buggers decide to lay...lol.

[PeteC]

Hopefully they're self-controlling whereas when the mealy bug population decreases, so does the wasp population proportionately. That is if there isn't another host they like here, like human earlobes. Pete

[PeteC]

I you were a wasp, could you tell the difference? Unknown answer until it happens I guess. First is the mealy bug, second is the Thai silk worm. Pete

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[Top Croc]

I worry when ever I hear "Introduction of ....species" to control something.

Luckily most times this is done the research backs up the introduction however there are times when the result is a disaster.

Most current day pests in Au that are proving impossible to control are introduced, the worst possibly being the cane toad.

In PNG several types of fish have been introduced as a protein supplement for river dwelling villages.
The result is a significant drop in native fish stock in one instance and a herbivorous eating fish that is destroying the nesting habitat of the salt water crocodiles.

Conversely a betel was introduced to control a water hyacinth, this was successful.

Lets hope the appropriate research has been conducted re the "African Wasp".

[PeteC]

Khun Sanitsuda Ekachai voices her concern. Pete

http://www.bangkokpost.com/opinion/opin ... er-ecology

[charlesh]

African wasps - IMO a recipe for disaster.
Introduced species have a verifiable history in other countries of at the best, mixed success! As was suggested in earlier post I hope they can ID mealy bugs and what happens when they run out next best no doubt given WASP behaviour. A case of any port in the storm to lay eggs and continue the species.