Weather and Desert Locusts

Manual and Guideline
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Desert Locust plagues can be an important contributing factor to famines and a threat to food security in many regions of the world. The Desert Locust plague of 1986–1989 and subsequent upsurges during the past two decades demonstrate the continuing capacity of this historic pest to threaten agriculture and livelihoods over large parts of Africa, the Near East and South-West Asia. In 2004–2005, a major upsurge caused significant crop losses in West Africa, with a negative impact on food security in the region. These events emphasize the need to strengthen and maintain a permanent system of well-organized surveys in areas that have recently received rains or been flooded, supported by a control capability to treat Desert Locust hopper bands and adult swarms efficiently in an environmentally safe and cost-effective manner.

The events of the 1986–1989 plague showed that, in many instances, the existing strategy of preventive control did not function well, for reasons which included the inexperience of the field survey teams and campaign organizers, lack of understanding of ultra-low volume spraying, insufficient or inappropriate resources and the inaccessibility of some important breeding areas.

These reasons were compounded by the general tendency to allow survey and control capacity in locust-affected countries to deteriorate during locust recession periods. Given the certainty that there will be future Desert Locust upsurges, the Food and Agriculture Organization of the United Nations (FAO) produced a series of guidelines and standard operating procedures primarily for use by national and international organizations and institutions involved in Desert Locust surveys and control.

The infrequency and brevity of locust plagues is welcome. However, long locust recession periods may be a source of problems. When a new campaign is needed, few national locust staff and even fewer pilots are likely to have campaign experience. Manpower and equipment resources on hand may have been diverted and, hence, are not available, or are insufficient, to run a campaign. Morale is likely to be low after a decade or more with only rare seasonal activity of any significance. Inexperienced staff from outside the national locust unit are likely to be deployed and every available sprayer used, whether suitable or not. Furthermore, lack of funds, bureaucratic rigidity and poor security in locust-affected countries can easily hamper a timely and effective response. When there is an upsurge, pesticide and aircraft are often supplied far in excess of what can be deployed currently, even by a well-trained, well-organized unit.

Furthermore, while the possible effects of climate change on Desert Locust are still under study, depending on the region, policymakers may have to prepare for longer locust seasons. This calls for strengthening international collaboration to better study the behavioural patterns of Desert Locusts in relation to changing meteorological and climatic conditions and to adapt control and preparedness plans.

FAO and the World Meteorological Organization (WMO) collaboration on Desert Locusts started in 1951, when the WMO Technical Assistance Mission for Desert Locust Control was established. Major movements of swarms were hypothesized to take place downwind, towards and within zones of convergent surface windflow. In 1981, meteorologists participated for the first time in the meeting of the FAO Commission for Controlling the Desert Locust in North-West Africa that was held in Algiers, 14–19 March 1981 (WMO, 1992). As the relationship between meteorological conditions and locust activity had been known for many years, the basis for cooperation with National Meteorological and Hydrological Services (NMHSs) was thereby established. Meteorologists from WMO Members have since been involved in national Desert Locust programmes and in joint action by WMO and FAO.

FAO is the lead agency in Desert Locust monitoring and control and runs the Desert Locust Information Service (DLIS). All locust-affected countries transmit locust and environmental data, as well as survey and control results, to DLIS for analysis, in conjunction with weather and habitat data and satellite imagery, in order to assess the current locust situation, provide forecasts of up to six weeks, and issue early warnings. FAO routinely prepares monthly locust bulletins and periodic updates forecasting the scale, location and timing of locust migration and breeding on a country-by-country basis. This information constitutes the early warning system operated by DLIS to alert countries and donors about the development of plagues. DLIS disseminates information by e-mail, the Locust Watch website ( and social media. In cooperation with affected countries, FAO undertakes field assessment missions and coordinates survey and control operations, as well as assistance during locust emergencies. To address the deterioration of survey and control capacity during recession periods, FAO has given high priority to a special programme, the Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases to strengthen national capacities.

As the authoritative voice on weather, water and climate of the United Nations system, WMO provides valuable assistance to FAO to ensure that WMO Members and their NMHSs provide near-real-time meteorological data and forecasts for locust-affected countries. WMO also maintains a Meteorological Information for Locust Control web page on the site of the World AgroMeteorological Information Service (WAMIS). WAMIS is a centralized web server that disseminates agrometeorological products issued by WMO Members ( locust/index.php).

The complex and serious nature of Desert Locust plagues demands that countries that are invaded and those that are threatened by them to work together across borders to find the best form of locust control. Desert Locust control is indeed an international responsibility, because locusts breed and move over wide areas so that events in one country rapidly affect events in others. Together, WMO and FAO have been helping to improve coordination and planning for potential locust outbreaks and control actions.

Petteri Taalas
WMO Director-General

José Graziano da Silva
Secretary-General, FAO