Cassava, Southeast Asia’s Rambo Root, Threatened By Invasive Pest Outbreaks

Cassava – a key crop for tapioca, animal feed, and biofuels – faces pest risks, according to new research discussed at the Climate Smart Agriculture Conference in Bangkok.

AsianScientist (Apr. 12, 2012) – Severe outbreaks of new, invasive pests triggered by rising temperatures could threaten Southeast Asia’s multi-billion dollar cassava industry, as well as the livelihoods of thousands that rely on the crop for income, according to research from the International Center for Tropical Agriculture (CIAT).

Thailand’s cassava industry accounts for more than 60 percent of global exports. It is one of the world’s biggest producers of tapioca starch, made from the cassava root.

In 2011, Thai farmers exported 2.8 billion metric tons of tapioca starch worth almost 48 billion Thai baht, according to the Thai Tapioca Starch Association.

For cassava in Southeast Asia, mealybugs and whiteflies are already endemic in the region. But new threats, such as the tiny green mite (Mononychellus mcgregori), are already emerging, says the research, published recently in the scientific journal Tropical Plant Biology.

The research was discussed at “Climate Smart Agriculture in Asia: Research and Development Priorities,” a conference convened in Bangkok this week by the Asia-Pacific Association of Agricultural Research Institutions (APAARI), the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), the World Meteorological Organization (WMO) and the United Nations Development Program (UNDP).

“One outbreak of an invasive species is bad enough, but our results show that climate change could trigger multiple, combined outbreaks across Southeast Asia, Southern China and the cassava-growing areas of Southern India,” said Tony Bellotti, a cassava entomologist at CIAT.

The green mite was first sighted feeding on cassava in Vietnam in 2009, with further reports from Southern China and additional unconfirmed sightings in Cambodia in 2011. It is closely related to the green mite species Mononychellus tanajoa, which has caused extensive damage to cassava in Africa and South America.

An invasive species, and with no natural enemies in Asia – green mite populations could explode if left unchecked.

Previous CIAT research identified cassava as a “Rambo root,” exceptionally tolerant of higher temperatures and droughts. But while the plant can survive the changing temperatures, in order to fully realize its potential to thrive in the face of climate change, it needs assistance in overcoming the crop pests that also come with modified climates.

In 2009, Thailand showed how a sudden, severe cassava mealybug outbreak could be swiftly brought under control through the use of the parasitic wasp Anagyrus lopezi, which was released into Thai cassava fields in 2010.


Source: CCAFS.
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