Uganda has confirmed an outbreak of crop-destroying worms known as "fall armyworms", an invasive pest that is rapidly spreading in the African continent, destroying crops.

Armyworms often spread in large numbers and consume nearly all plants in their path, earning them their name. The armyworm is actually a moth, and the hungry caterpillars are the form in which it eats crops including maize, rice, soybean and cabbage, before turning into a moth.

Outbreaks have been reported in Southern Africa, and other countries are gearing up to tackle a similar invasion.

Uganda's Agriculture Minister, Vincent Sempijja said on 24 March the caterpillar's presence has been confirmed in 20 out of 111 districts across the country – some 18% of the territory.

Earlier this month, Sempijja urged farmers to remain calm and assuring them measures were being sought to fight the caterpillars, but on 24 March, he said that more than 40% of maize crops have been destroyed in the first three areas where armyworm had spread to.

The government has set aside USh1bn ($300,000, £240,000) for an emergency response to the outbreak.

In its March 2017 assessment, the United Nations (Office for the Coordination of Humanitarian Affairs (OCHA) stated that the outbreak could have "severe impacts on crop production, food security, nutrition and livelihoods in the region".

The problem is reportedly compounded by the recentness of the pest, which hails from South America, and its resistance to common pest control chemicals.

In addition, the armyworm is classified as a quarantine pest. This means that any infestation could potentially affect Uganda's food trade with other nations.

The pest was first detected in Zambia in December 2016, Malawi and Zimbabwe in January 2017, Botswana, South Africa and Swaziland in February 2017. The moth has also been reported in Namibia, Tanzania and Mozambique.