Armyworm looking for world domination

CONQUEST: The fall armyworm is on the march for global conquest. (Photo: Centre for Agriculture and Bioscience International)

AFTER taking only two years to invade and spread throughout most of sub-Saharan Africa, the American pest fall armyworm is showing its huge potential to severely impact livelihoods worldwide.

Researchers warn this means important crops throughout the world are at serious risk if efficient measures are not taken, including maize, rice, sugarcane, sorghum, beet, tomato, potato, cotton and pasture grasses.

A study by Exeter University in the UK and the Centre for Agriculture and Bioscience International says alarm bells rang in January 2016 when major outbreaks of armyworms occurred in Nigeria and Ghana, ahead of Benin, Sao Tomé and Togo.

By September 2017, the pest was in 28 sub-Saharan African countries.

The researchers speculate the pest arrived in Africa on a passenger flight from America. They point out the first countries to house the invader are also the major air transportation hubs in Africa and have warm, moist climates similar to those in the pest’s natural habitat.

In the aftermath, recent estimates point to up to 50 per cent maize yield loss in Africa attributed to the armyworm.

To find where it will appear next, the researchers looked into both the native and African distributions of the species, and the effects different temperatures and precipitation levels have on it.

As temperatures and rain play the main role in determining whether the fall armyworm is to establish in a certain region, the scientists conclude that South and Southeast Asia, as well as Australia, face the most serious risk, since their climate is very similar to the one preferred by the pest.

But that is not a pass for other countries. While the moth needs particular temperature and precipitation levels at its year-round habitat, it could easily travel back and forth up to several hundred kilometres during its seasonal migrations.

Thus, if the armyworm establishes in North Africa, it could migrate to Europe during the warmer months, just as it now travels from year-round localities in Argentina, Texas and Florida north to Canada’s Quebec and Ontario.

The scientists conclude that, given current travel air routes, it is Australia, China, India, Indonesia, Malaysia, Philippines and Thailand that are at high risk of becoming the pest’s new habitat.


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