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Desert Locust situation update 18 May 2016

Swarms likely to form in Yemen

The Desert Locust situation continues to remain extremely alarming in Yemen. Breeding is in progress in the interior desert where good rains fell in November from two cyclones and again in April. As a result, ecological conditions continue to be favourable and locust numbers are increasing. Hatching and hopper band formation are currently under way. Hoppers will start to fledge in about two weeks and the new adults will form immature swarms from early June onwards. These swarms are expected to fly about within the interior as long as vegetation remains green.

The scale of the current outbreak is not well known. The few national survey teams currently active in the field cannot check many areas due to insecurity and remoteness. So far, teams have found hoppers bands in central areas of Wadi Hadhramaut and in numerous wadis on the rugged plateau to the north between Thamud and Minwakh. This area is extremely remote and difficult to access. Consequently, only a small portion of this area has been surveyed so far. Hopper bands have also been reported in desert areas west of Al Abr and near Bayhan as well as on the southern coast near Aden. This suggests that breeding has occurred over a large portion of the interior and many more locust infestations are likely to be present than are currently reported.

In the past few days, ground teams treated 39 ha but control operations are hampered by insecurity, remoteness and the presence of beekeepers and herders. Once swarms do form, control operations will become more difficult.

If breeding conditions continue to remain favourable in the interior of Yemen, there is a possibility that the swarms which form will move about between Marib and Thamud, mature and lay eggs from early July onwards. If so, this will result in a further substantial increase in locust numbers. On the other hand, if vegetation starts to dry out, then the swarms are likely to move south in June towards the Gulf of Aden where the southwest monsoon winds could carry them to the summer breeding areas along both sides of the Indo-Pakistan border in time for the arrival of the seasonal monsoon rains.

All efforts are required to mobilize additional field teams for survey and control operations in the interior of Yemen wherever it is safe and possible in order to determine the extent of current infestations and reduce swarm formation and subsequent breeding or migration.

Previous updates

Latest Desert Locust Bulletin (No. 451, April 2016)

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Press Release (12 April 2016)

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Previous Desert Locust Bulletin (No. 450, March 2016)

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Current situation in Yemen (click for larger view)


Current Desert Locust threat (click for larger view)