Despite ongoing control efforts, humanitarian agencies remain concerned about the desert locust situation in Ethiopia, Kenya and Somalia, with the UN Food and Agriculture Organization warning that the continued risk of the current upsurge could develop into a plague by the end of 2020.

Bands of hoppers, immature, wingless locusts, have formed in all three countries, and will begin developing into immature swarms in the coming days.

The new swarms are projected to spread to previously unaffected parts of Ethiopia, reaching as far as the country's northern highlands in July.

Infestations will likely also extend further into additional areas of Djibouti, Eritrea, Somalia, and Sudan during June, according to FAO.

Relief agencies are also concerned that unmitigated breeding in Yemen, where conflict and coronavirus-related restrictions are hindering efforts to scale up surveillance and control interventions, could amplify the scale of the current upsurge.

Breeding is underway along the southern coast and in the interior of Yemen, and subsequent swarms could invade Ethiopia and Somalia or travel east into India and Pakistan, depending on wind patterns.

The food and agricultural organization said without additional rain, locusts are unlikely to remain in Kenya for a third generation of breeding.

Aided by prevailing winds, swarms will reinvade adjacent parts of Ethiopia, moving into the Rift Valley and continuing on to Ethiopia's Afar, Amhara, Dire Dawa, and Tigray regions, where recent rainfall and subsequent flooding have produced suitable breeding conditions.

Other swarms also are expected to traverse South Sudan and enter southern Sudan's summer breeding areas in the coming weeks.

Meanwhile, desert locusts have continued to damage vital pastureland in affected areas of East Africa in recent months, adversely impacting the livelihoods of pastoral populations in eastern Ethiopia and northern Somalia in particular, according to the Famine Early Warning Systems Network.

Additionally, the formation of new, immature swarms, the stage when locusts are most voracious and mobile, coincides with the beginning of the harvest season in parts of the region, further threatening food security and livelihoods in affected areas.

The UN organization said effective control measures are critical for safeguarding crops as the harvest in Ethiopia and first season harvests in parts of South Sudan begin in June, as well as preventing damage during the anticipated harvest in Somalia in July and long rains maize harvests in eastern and northern Kenya in July and August.

According to the World Bank, unless infestations in East Africa and Yemen are adequately contained, damage and losses caused by the pests could reach up to an estimated $8.5 billion by the end of 2020. Ethiopia will be most affected, with potential losses valued at up to $2.8 billion.

The Famine Early Warning Systems Network expects locusts to cause significant damage to cereal crops in agro-pastoral areas of northwestern Somalia during June. The pests could impact the harvest if infestations spread to southern areas of the country in July.

"Locust and flood-related damage alone may reduce agricultural yields in Somalia by 10 to 15 percent compared to the long-term average," FAO said.

The agency adds that in the absence of sustained, large-scale humanitarian assistance, up to 3.5 million people across Somalia could face crisis or worse levels of acute food insecurity in the coming months.

Based on preliminary assessments, the food and agricultural organization estimates that locusts could devour up to 20 percent, or approximately 40,000 metric tons, of crops in affected areas of South Sudan, an amount sufficient to feed approximately 278,000 people for one year.

Households in the country are already facing limited food access due to the impact of coronavirus mitigation measures, unusually heavy flooding in late 2019, ongoing conflict, poor macroeconomic conditions, and high food prices.

The food and agricultural organization said coronavirus-related movement and shipping restrictions continue to impact desert locust response in several countries. Planned operations in Sudan have been delayed, with the Sudan's Plant Protection Department unable to dispatch supplies and equipment as rapidly as planned.

The restrictions also have delayed the delivery of approximately 30,000 liters of pesticides in Kenya.