DAR ES SALAAM, Jan. 18 (Xinhua) -- At least 400 hectares of maize field in Tanzania's northern district of Arusha are on the brink of destruction after an invasion of fall armyworms, destructive pests that are threatening food security in some parts of the country, an expert said Thursday.

Bahati Ndillahomba, a plant protection officer in Arusha district, said the armyworms have invaded farms in the district, causing extensive damage in most maize fields.

"This is a serious problem, which could get out of control if not well handled," warned Ndillahomba.

Erwin Kinsey, Director of ECHO East Africa Impact Center, appealed to the experts in the agricultural sector to come up with ways to put an end to the threat of the pests.

Kinsey said the invasion should serve as a wake-up call on the farmers' preparedness on averting the invasion.

Unlike the African armyworm, the fall armyworm originates from the Americas. They are difficult to detect and can cause rapid and full destruction of the crops.

Last year, the UN Food and Agriculture Organization entered into two agreements worth 2 million U.S. dollars with Tanzanian government to boost surveillance of fall armyworms.