Agriculture Minister Onyoti Adigo told reporters some 2,000 locusts have been spotted inside the county, adding that authorities will try to control the outbreak.
The locusts have been seen in the South Sudanese state of Eastern Equatoria near the borders with Ethiopia, Kenya and Uganda. All have been affected by the outbreak that has been influenced by the region’s changing climate.
The U.N. Food and Agriculture Organization, in its latest Locust Watch update Monday, said the situation “remains extremely alarming.”
The soil in South Sudan's Eastern Equatoria has a sandy nature that allows the locusts to lay eggs easily, said Meshack Malo, country representative with the FAO.
At this stage "if we are not able to deal with them ... it will be a problem," he said.
South Sudan remains especially ill-prepared to deal with the outbreak. More than 5 million people are severely food insecure, while 860,000 children are malnourished, according to the U.N. humanitarian office.
Five years of civil war shattered South Sudan's economy, and lingering insecurity since a 2018 peace deal continues to endanger humanitarians trying to distribute aid. Another local aid worker was shot and killed last week, the U.N. said Tuesday.
The locusts have traveled across the region in swarms the size of major cities. Experts say their only effective control is aerial spraying with pesticides, but U.N. and local authorities have said more aircraft and pesticides are required. A handful of planes have been active in Kenya and Ethiopia.
The U.N. has said $76 million is needed immediately. On Tuesday, U.S. Secretary of State Mike Pompeo during a visit to Ethiopia said the U.S. would donate another $8 million to the effort. That follows an earlier $800,000.
The number of overall locusts could grow up to 500 times by June when drier weather begins, experts have said. Until then, the fear is that more rains in the coming weeks will bring fresh vegetation to feed a growing population of the insects.
The Associated Press contributed to this report.