Thailand in “sting operation” to kill cassava pest

15 July, 2010 by (comments)
Eco-efficient South American wasp to seek-and-destroy mealybug plague
A carefully crafted emergency campaign is underway to thwart a pest outbreak wreaking havoc on cassava production in Thailand.

Agricultural researchers from the Thai Department of Agriculture will release around a quarter of a million parasitic wasps in the northeastern part of the country tomorrow (July 17), as a form of biological control. The aim is for the Anagyrus lopezi wasp to hunt down and kill mealybugs. You can see the full press release here shortly.

Anagyrus lopezi

We reported on the devastating cassava mealybug (Phenacoccus manihoti) outbreaks sweeping across Thailand here on the CIAT blog in January. At the time CIAT scientists in SE Asia raised the alarm and issued emergency guidelines to try and help contain the spread, while long term eco-efficient solutions were sought.

Now, scientists hope that one such solution is the tiny A. lopezi wasp.
Like the cassava plant and the cassava mealybug, the wasp is native to South America, and is a formidable natural enemy of mealybugs. Even when infestations are low, A. lopezi has the remarkable ability to hunt down mealybugs and lay its eggs inside them. The wasp larvae grows and feeds on the host insect, eventually killing it and helping to reduce the pest population.

thailand 14_lo

After several months of rearing and research, the Thai DoA is expected to officially start the release of the wasps in the northeastern province of Khon Kaen, with further releases in different sites expected to follow soon after. The wasps pose no threat to humans, animals, or other insects – and will help farmers to control mealybugs without the need for pesticides.

Dr Amporn Winotai, a senior entomologist for Thailand’s Department of Agriculture, said: “Cassava is an important crop for small-scale farmers in our country, so there’s no time to lose in applying the fastest, most reliable solution available.”
CIAT entomologist Tony Bellotti has spent 35 years investigating cassava pests. “Sending in the wasps is a proven way to kill the cassava mealybugs quickly and effectively,” he said.
“Think of them as a kind of eco-friendly SWAT team.”
And they couldn’t arrive sooner: Thailand’s cassava industry, which accounts for more than 60 percent of global exports, is suffering. The mealybug has spread to about 200,000 hectares in the east and northeast of the country, where it is causing yield losses as high as 50 percent. The outbreak has also reached cassava fields in neighbouring Cambodia, Burma and Laos.

Around 5 million small producers across Southeast Asia supply cassava to domestic and foreign processing industries, which convert the roots to animal feed and biofuels and also extract starch for use in a wide variety of food and other products.

“Cassava production in Southeast Asia has enjoyed an extended honeymoon, relatively free of major pest and disease outbreaks,” continued Bellotti. “But now it’s over.”

“It’s going to be an international game of cat-and-mouse,” he said. “As the cassava mealybug finds its way to new countries and regions, we can send in the wasps.”

Bellotti was part a team of scientists from CIAT and CGIAR sister center the International Institute of Tropical Agriculture (IITA) that originally collected A. lopezi from the wild in Brazil in the 1980s. The wasp was quickly proven to be an extremely effective form of biological control, with CIAT, IITA and other partner organizations successfully deploying it to curb mealybug outbreaks in sub-Saharan Africa and helping to avert a food security crisis.

The work resulted in lead scientist Hans Herren receiving the World Food Prize in 1995, and CIAT and IITA earning the CGIAR’s 1990 King Baudouin Award, which recognizes outstanding contributions to developing country agriculture.

CIAT’s director general Ruben Echeverría congratulated the international effort to tackle the outbreak. “Thailand’s rapid response to stop the cassava mealybug plague shows international agricultural research at its best,” he said.

“This is why it’s so important for developing countries to have strong research programs working closely with the international centers like CIAT and IITA.”
We’ll bring you the latest on the efforts to tackle the mealybug situation in Thailand and the region – so stay tuned.

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Filed Under: Asia @en, Cassava @en, Crops @en, Latin America and the Caribbean, Regions