A third fire ant infestation has emerged at Nagoya port, following two similar discoveries last month in Kobe, the Aichi Prefectural Government said Friday.

The aggressive reddish-brown ants, highly invasive and native to South America, are feared for their painful stings. The pest, formally known as Solenopsis invicta, is commonplace in United States and reportedly in China and Taiwan.

Environment Minister Koichi Yamamoto said the ministry will conduct further inspections for the ant at the seven major ports — Tokyo, Yokohama, Nagoya, Osaka, Kobe, Hakata and Naha.