Tiny killer wasps deployed in first phase to thwart food security threat in Indonesia

25 September, 2014 by (comments)
Scientists released 3,000 tiny parasitic wasps into a confined cage on Wednesday.

Scientists released 3,000 tiny parasitic wasps into a confined cage on Wednesday. Credit: Georgina Smith / CIAT

A team of around 3,000 tiny parasitic wasps have been released into a confined cage in Indonesia, in the first phase to stamp out a major pest afflicting cassava in Southeast Asia.

Cassava is a key crop in Indonesia, which is among the world’s major cassava producers. More than one million hectares of cassava is planted every year, half of which is directly consumed as a staple food. The crop is also used in the starch industry to make products as diverse as plywood, paper, sweeteners and pharmaceuticals, supporting smallholder incomes.

But the cassava pink mealybug (Phenacoccus manihoti) – one of the world’s most destructive cassava pests – has spread through the region and is now poised to devastate Indonesia’s second major staple crop after rice, jeopardizing cassava-based livelihoods, food security and the growing starch industry.

“Cassava directly supports millions of small-scale farmers in Indonesia and has enjoyed a period of being relatively pest-free from certain threats,” said Dr. Aunu Rauf, professor of agricultural entomology at Bogor Agricultural University in Indonesia, co-leading the wasp release with CIAT and the Food and Agriculture Organization of the United Nations (FAO).

“But now, pests have caught up,” he added. “We have to take rapid, environmentally sound measures to ensure livelihoods are protected and Indonesia’s food security is not compromised. If we don’t act now, this could be a major blow to the country’s cassava industry and to the millions of farmers who depend on this crop for their incomes,” he said.

The tiny, two-millimeter Anagyrus lopezi wasps, released inside a confined cage in an infected field on Wednesday, deposit their eggs into the mealybug. The hatching larvae consume the mealybugs from inside, slowly mummifying and killing them.

The Anagyrus lopezi wasp

The Anagyrus lopezi wasp

These efforts are part of a much bigger project addressing cassava threats and diseases in the region, funded by the European Union through the International Fund for Agricultural Development (IFAD) – will allow researchers to ensure the wasps adapt to local conditions and gives them time to reproduce naturally before an open field release goes forward.

The wasps have already proven their economic clout in sub-Saharan Africa, where they saved a whopping US$20 billion in damages to the cassava industry and averted a food security crisis for millions of smallholder farmers. The continent-wide airplane release operation in the 1980s exceeded the cost of research by a factor of more than 200.

These wasps pose no threat to humans, animals or other insects and feed only on cassava mealybug, say researchers, and this method of biological control is better than sweeping fields with pesticides, which could have disastrous environmental impacts.

Cassava pink mealybug is capable of reducing cassava yields by up to 84 percent. It was first reported in Thailand in 2008, subsequently spreading throughout the Greater Mekong Subregion – a region that includes Cambodia, Laos, Myanmar, Thailand, Vietnam and the Yunnan Province in China.

Now, it appears in Indonesia’s major cassava producing areas, including Lampung and Java. Although the current area affected is still low, the pest can spread fast if not managed, as already happened in Thailand in 2009.

“Cassava is originally from South America, so it makes sense that the crop’s pests come from there too,” said Dr. Kris Wyckhuys, CIAT’s entomologist in Asia. “With no effective threats or natural enemies in their newly invaded continent, cassava mealybugs have been living in the lap of luxury first in Africa, and now in Asia. It’s time to help nature along and send in mealybugs’ natural parasitoid,” he added.

A network of researchers spearheaded by CIAT and regional partners are staying ahead of the curve by investing in diagnostic and training programs to speed up pest and disease detection. Scientists are developing low-cost rapid pathogen detection kits, while gaining valuable insights into the biology and ecology of non-native cassava threats.

Dr Aunu Rauf co-lead the wasp release.  Credit: Georgina Smith / CIAT

Dr Aunu Rauf co-lead the wasp release. Credit: Georgina Smith / CIAT

“Invasive species have become an increasing threat to global economies, societies and ecosystems,” said Jan Willem Ketelaar, an FAO expert on integrated pest management. “Throughout the world, a diverse and growing group of invasive organisms is causing billion-dollar losses in direct management costs, in addition to inflicting substantial effects on the environment and trade,” he said.

Dr. Rangaswamy Muniappan, director of the Integrated Pest Management Innovation Lab, Virginia Tech, and funded by USAID a key partner in the release operation – said: “Ultimately, both farmers and researchers have to stay ahead of the curve to respond to this and other possible destructive cassava threats, now and in future, in swift and environmentally friendly ways.”

In the long-term, CIAT together with national and international partners will continue investigating more resilient cassava varieties and better crop and integrated pest management systems, as well as quarantine measures to stem the spread of pests and diseases in the region.

“This sting operation, gives the region’s cassava farmers a reprieve from a devastating pest. But we know it is not the last such threat,” said Dr. Wyckhuys.“Scientists and farmers must continuously advance the science of crop production and protection to keep ahead of even the seemingly innocent mealybug.”


Filed Under: Asia @en, Cassava @en, Crops @en, Regions