For many centuries, the Desert Locust has been seen as a major threat to the agro-pastoral resources in
the world’s most warm and temperate climates, including South of the Sahara. Schistocerca gregaria
(Forskal, 1775), in the Acrididae family and Cyrtacanthacridinae subfamily has always been the most
feared. Its first written presence was over 3000 years ago, it has especially been noted in sacred books
(Torah, Bible and Koran). The plague of this phytophagous can be extremely destructive and cause
substantial losses to crops and pastures. Many confirm that although intermittent, the locust ravages span
from the Middle Ages to the present.
The population dynamics of this Trans-boundary pest alternate during periods of recession (solitary
phase), upsurge, outbreak (transient phase) and plague (gregarious phase). In recession, the locust remains
dispersed: in a solitary or transient form, with the possibility of reproduction in restricted areas to less than
40% of the plague area and covering the desert areas ranging from West Africa to Southwest Asia, the area
of breeding has reached about 13.6 million km?. In case of plague, it threatens about 60 countries,
agriculture and grazing, including some of the world’s poorest. These countries cover a total area of more
than 31 million km?, nearly 25% of the land inhabited by a tenth of the world’s population.
The range of the locust breeding area is divided into three regions: Western, Central and Eastern. The
exchange of populations between the various parties and different areas of the same sub-region are
numerous and frequent, especially between East Africa and West Africa. They are seasonal and regular
between the Saharan-Sahelian zones of Africa and the Northwest. Since 1860, eight periods of plague
have succeeded, with durations ranging from 3 to 22 years. In addition, over the last 40 years, four major
outbreaks were observed: 1968, 1987/88, 1993-95 and the last in 2003-05 in the western region. The
results of an independent evaluation of this last outbreak shows that in the Sahel, over 8 million people
have suffered from the plague while agricultural losses have affected 80-100% of the expected crop. The
plague has made the long-term food security of local people even more uncertain. Increasing poverty and
vulnerability of populations, already, living in precarious conditions.
International coordination for this plague was made on behalf of countries and the United Nations by
Food and Agriculture Organization (FAO), which has a group and an information and forecasting service
dedicated to this activity and three regional commissions. To be effective in prevention, countries of the
recession area must maintain an institution that is consistently vigilant, well-equipped with material and
qualified human resources. In our western region (Sahel-Maghreb), most countries have developed,
established and maintained institutional structures while adapting preventative control methods. This can
be attributed to the anti-locust policy initiated by the Locust Commission in charge of the coordination in
Western Region (CLCPRO) as well as to all their countries members, their strong determination in addition
to continued solidarity between them and the support of their partners: World Bank, African Development
Bank, France, Food and Agriculture Organization, the Emergency Prevention System (EMPRES), USAID,
Japan, etc. However, further constraints to overcome for the full implementation remain. Particularly in
some front line Sahelian countries, including insufficiency of budget and security problems in the
gregarious and breeding areas.
As an example: Mauritania, which is a sahelian country, shelter many permanent habitats and outbreaks
areas of the Desert Locust, Schistocerca gregaria. Since the 1950’s, a preventative control strategy was
progressively applied in various organizational and operational forms, in particular by the OCLALAV, a
regional locust control organization. The Mauritanian government began to take over the responsibility
for Desert Locust survey and control in 1980. A specialized national unit in charge of early warning and
early control operations was created in 1989, then transformed into a National Anti-locust Center in 1995
and finally upgraded as an autonomous institution since 2006.The Mauritanian National Anti-Locust Centre (CNLA) is charged with monitoring and controlling the
desert locust to contribute to the fight against poverty and to the security of food supplies, in Mauritania
and neighboring countries. The Centre promotes preventive controls to break the breeding sequence by
intervening as early as possible against gregarious populations. This means that well-directed and correctly
implemented surveys are necessary to provide precise information on the locust and to allow early warning
and rapid treatment in a safe and effective manner. When high densities of the locust are found along with
favorable ecological conditions, a decision is taken on whether to control the population. The decision
depends on the location, behaviour, maturation and density of infestations of the locust, as well as on the
resources available. Pesticides and application methods are chosen so as to provide control that does as
little environmental harm as possible. The centre is constantly looking to improve its methods, making
sure that pesticides are used efficiently and with minimal environmental impact. Since 1985, increasingly
regular survey and control campaigns have been led, as well against invasions (1987/88, 1993/94,
2003/2005) as against local outbreaks. Significant investments have been made, by the Mauritanian
government with the collaboration of his partners, in the capacities development, particularly, the human
resources’, the infrastructures, logistical equipment and all potential working tool such as: remote sensing,
high technological tool for information transmission, Data base and GIS. As example: the biggest locust
database in the affected countries was made up, computerized and exploited; it resulted in an improvement
of survey operations and in a reduction of the costs from approximately 30%. A decision-making system
for the management of locust control campaigns was developed too. Research was undertaken to study the
possibility to introduce, in preventative locust control, biological products as an alternative to chemical
pesticides and also to covers many others fields key topics in a very wide international collaborative
partnerships including JIRCAS.
Comparative analysis of the respective costs of control campaigns against invasions and preventative
control campaigns shows a net financial advantage in favors of the last, the costs being able to be in this
case 100 times lower.
Mauritania holds, however, only a part of the problem since the outbreak areas of the Desert Locust are
widely distributed in other countries, which must also develop, in a coordinate manner, their own system
for survey and control.