Action now, warn experts, as pests threaten Indonesia’s food security crop

14 December, 2013 by (comments)
Pink mealybug originated in South America and have since spread around the world. Pic: Georgina Smith / CIAT

Pink mealybug originated in South America and have since spread around the world.

If there’s one thing being at the top of the food chain affords you, it’s time. Time spent combating what could potentially wipe you out of existence can be much more productively spent on other things – like eating.

And eating is what one major pest has done a lot of since it arrived in West Java, Indonesia. Discovering itself in virtual paradise with no indigenous predators, the “pink mealybug” has munched its way through half of local cassava fields.

A move, researchers say, which brings the pest dangerously close to engulfing the entire country’s major staple crop, eating at the heart of local food security and taking a big bite into the increasingly important cassava industry’s feed-stock.

Cassava is the third most important source of carbohydrates in Southeast Asia after maize and rice, and the region produces over 35% of the world’s crop. Indonesia produces roughly 1.5 million hectares of cassava – of which about half is used directly as a food crop.

Phenacoccus manihoti, or pink mealybug as it’s also known locally, is one of the most destructive cassava pests in the world,” explains leading regional pest expert for the International Center for Tropical Agriculture, Dr Kris Wyckhuys.

The spread of the pink mealybug is being fueled by unchecked, inter-country and inter-continental movement of cassava stakes, with waves of different invasive pest species having recently arrived in the region.

Of South American origin, the pest spread to Africa in the 1970s. It caused havoc there – then, alarmed scientists detected it in Thailand in 2009. It has since spread, despite serious action taken, and is now establishing itself in Indonesia.

Experts including Takumasa Kondo, Corpocia, gave insights on diagnostic methods at the  International Workshop on Invasive mealybugs in Southeast Asia

Experts including Takumasa Kondo, Corpocia, gave insights on diagnostic methods at the International Workshop on Invasive mealybugs in Southeast Asia

Heading for sunny climes

“The pink mealybug is having a great time. Indonesia not only boasts the ideal climate to support its populations, there are also no natural enemies that traveled with it, and so it has found itself living in luxury,” said Dr Wyckhuys.

But not for long, should researchers get their way. A clamp-down event launched in Vietnam by CIAT, supported by the International Fund for Agricultural Development (IFAD), is the first to fully focus on the threat – and what to do next.

“Accurate species identification and in-depth knowledge of the pest’s biology and ecology are key ingredients to an effective control program for the region,” said Dr Aunu Rauf, Professor of Agricultural Entomology at Bogor Agricultural University in Indonesia, speaking at the three-day workshop which brought together prominent mealybug specialists and insect ecologists from around the world.

“We hope to have planted the seed for long-term control not only for cassava mealybug, but for many other invasive pests in the region.”

Insights into pest diagnosis Pic: Georgina Smith / CIAT

Insights into pest diagnosis. Pictures: Georgina Smith / CIAT

Unleashing the enemy…

But the South American wasp Anagyrus lopezi, which seems to have a preference for pink mealybug, could be Indonesia’s only answer to the emerging threat. In rather gruesome fashion, this miniature wasp lays its eggs inside the pink mealybug – and pink mealybugs only – putting a deadly end to their care-free holiday.

Initial figures show the wasp is doing a relatively good job at lowering mealybug population levels in the Southeast Asian countries where it has previously been released.

Indonesian researchers, having confirmed that natural predators are not up to the job of keeping pink mealybug under control, are now looking into the possibility of importing the wasp.

In the meantime, regional researchers have emerged from three days of training equipped with diagnostic methods to detect and monitor the spread of the bug.

“I have more knowledge about the ecology of the pink mealybug – I didn’t know about its importance before and this workshop has provided information essential to many of the region’s plant health officers and quarantine entomologists,” said Khanxay Somchanda, an entomologist from Lao PDR’s Plant Protection Center under the Ministry of Agriculture and Fisheries.

Throughout next year, information about the pink mealybug threat will be extended to farmers in Laos, Myanmar, China, Vietnam, Cambodia, Thailand and Indonesia, in an effort to put a firm close to Phenacoccus manihoti’s long over-due stay in the region.


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