This could result in potentially adverse impacts on the agricultural seasonal yields and local economies affecting food security and livelihoods of the populations in the countries concerned.
Intensive ground and aerial control operations were mounted in Iran (712 000 ha), Saudi Arabia (219 000 ha) and Sudan (105 000 ha) this year that reduced locust populations but could not entirely prevent swarms from forming and moving to the traditional summer breeding areas in Yemen, Sudan, the Horn of Africa and along both sides of the Indo-Pakistan border.
There is a moderate to high risk of the Desert Locust situation escalating further in the interior and coastal areas of Yemen and in the interior of Sudan, causing swarms to form that would threaten agricultural production by the end of the summer. This will be followed by further increases along both sides of the Red Sea during the upcoming winter from November onwards.
Yemen, the world's current worst humanitarian crisis, is the most concerned and at highest risk because of widespread hopper band infestations and heavy rainfall that will cause swarms to form from this week onwards, which could give rise to another generation of breeding by the end of August if weather conditions remain favourable to locust breeding.
In the worst-case scenario, swarms could migrate from Yemen in the autumn to the Horn of Africa and reach Kenya by the end of the year, unless urgent preventive and control measures are established in the region. Desert Locust swarms last invaded Kenya in 2007 and aerial control operations were required to bring the situation under control.
In northeast Somalia, mature swarms were seen at several locations during the past weeks, causing substantial crop damage. Hopper bands are now forming along the northwest coast and probably in the northeast from eggs laid by the swarms. This could give rise to new swarms by about late August.
Similar breeding is expected to occur in eastern Ethiopia while groups of adult locusts may move from the northern region of Amhara to the summer breeding areas in western Eritrea and the interior of Sudan.
In Sudan, high numbers of adult populations are present in the Nile Valley while scattered adults appeared recently on the Red Sea coast and in North Kordofan where summer breeding will occur.