Army worms eat maize leaves as they attack a maize garden in Ngong township, Kenya May 19, 1999. REUTERS/George Mulala

MONROVIA (Reuters) - Swarms of army worms have attacked crops in a food-producing district of Liberia, forcing the West African state to declare a state of emergency in the area at the weekend, the Ministry of Agriculture said on Monday.

Army worms, which can grow to around 5 centimeters (two inches) in length, are moth caterpillars and when present in large numbers can destroy swathes of vegetation and crops.

“We are calling for international assistance to combat these insects. They have affected over 19 villages in Bong county,” Agriculture Minister Christopher Toe told Reuters.

In earlier comments quoted by local media, Toe said the army worms were consuming crops and polluting running water sources with their droppings in Bong county’s Zota district, which borders on neighboring Guinea. The minister met local and foreign experts on Monday to try to coordinate a response.

Local residents reported the caterpillars were also infesting buildings and homes in their search for food.

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