YAOUNDE (Reuters) – Crop-eating fall armyworms have attacked nearly 37,000 hectares of maize in northern Cameroon, officials said on Wednesday, accentuating an already dire humanitarian crisis provoked by the Islamist militant group Boko Haram’s cross-border insurgency.

More than two dozen African nations have reported outbreaks of the invasive Central American variety of the pest, which is harder to detect and eradicate than its African counterpart.

They have now spread to all of Cameroon’s 10 administrative regions, though maize crops in the Extreme North region have only been heavily affected since July, Deputy Agriculture Minister Clementine Ananga Messina told Reuters.

“The armyworm attack endangers the entire maize sector and is creating serious risks of food insecurity, because it’s the most commonly grown cereal in Cameroon,” she said.

The Extreme North region bordering Chad and Nigeria has been hit hard by Boko Haram, whose campaign of violence and cross-border attacks has sent more than 93,000 Nigerians fleeing into Cameroon where some 235,000 people have also been displaced.

Across the Lake Chad region around 1.5 million people are confronting a food crisis, according to the United Nations.

Cameroonian authorities have launched an action plan to fight against the infestation, but so far pesticides have failed to contain it.

“There are no effective means to fight armyworm currently existing in Cameroon,” said Agriculture Ministry expert Andre Marie Elombat Assoua. “The chemical products now being used by farmers are ineffective and too expensive.”

Around 12 million Cameroonians, more than half of the national population, regularly consume maize. It is also an important ingredient for the central African nation’s breweries and in the production of feed for livestock.

Though the fall armyworm prefers maize, it also attacked sorghum and millet, two of Cameroon’s other staple crops, earlier this year.

(Reporting by Anne-Mireille Nzouankeu; Writing by Joe Bavier; Editing by Alison Williams)