Tiny pests are causing big problems in the African country of Liberia.
A plague of caterpillars is munching its way through farmers' valuable crops, causing food shortages and contaminating water.
The president of Liberia, Ellen Johnson-Sirleaf has declared a state of emergency, saying some 400,000 people in 100 villages have been affected.
It was thought the caterpillars were common armyworms, but now experts say they're the Achaea caterpillar species.
They may be tiny, but the caterpillars can travel up to 60 miles a day, and have already been spotted eating away at crops in neighbouring Guinea.
But there is some good news - bug experts say this species of caterpillar should be easier to get rid of than the armyworms as they stay above the ground.
Both countries are now using chemicals to destroy the bugs and protect their crops.
It's thought the plague could be the result of an unusually long rainy season last year.