Locusts are part of a large group of insects commonly called grasshoppers which have big hind legs for jumping. Locusts belong to the family called Acrididae. Locusts differ from grasshoppers in that they have the ability to change their behaviour and habits and can migrate over large distances. The Desert Locust is one of about a dozen species of short-horned grasshoppers (Acridoidea) that are known to change their behavior and form swarms of adults or bands of hoppers (wingless nymphs). The swarms that form can be dense and highly mobile. The Latin name for Desert Locust is Schistocerca gregaria (Forskal).
During quiet periods (known as recessions) Desert Locusts are usually restricted to the semi-arid and arid deserts of Africa, the Near East and South-West Asia that receive less than 200 mm of rain annually. This is an area of about 16 million square kilometres, consisting of about 30 countries.
During plagues, Desert Locusts may spread over an enormous area of some 29 million square kilometres, extending over or into parts of 60 countries. This is more than 20% of the total land surface of the world. During plagues, the Desert Locust has the potential to damage the livelihood of a tenth of the world's population.
When conditions are favourable for reproduction, locust numbers increase and when they are not, numbers decrease either by natural mortality or through migration. For the Desert Locust, favourable conditions for breeding are (1) moist sandy or sand/clay soil to depths of 10-15 cm below the surface, (2) some bare areas for egg-laying, and (3) green vegetation for hopper development. Often favourable conditions may exist in the desert but there are no locusts present. Therefore, the presence of moist soil and green vegetation does not automatically mean that there are locusts around!
Weather satellitesand other satellites used to monitor the environment cannot detect locust individuals or swarms. However, the highly sophisticated satellites used by the military can indeed detect locusts but these images are not available. Even if they were, it is unlikely that national and international locust organizations would have the ability to interpret the hundreds of images that would be produced on a daily basis.
Difficulties in Removing Locust
There are many reasons as to why it is difficult to successfully combat the Desert Locust. Some of these are: (1) the extremely large area (16-30 million sq. km) within which locusts can be found, (2) the remoteness and difficult access of such areas, (3) the insecurity or lack of safety (such as land mines) in some areas, (4) the limited resources for locust monitoring and control in some of the affected countries, (5) the undeveloped basic infrastructure (roads, communications, water and food) in many countries, (6) the difficulty in maintaining a sufficient number of trained staff and functioning resources during the long periods of recession in which there is little or no locust activity, (7) political relations amongst affected countries, (8) the difficulty in organizing and implementing control operations in which the pesticide must be applied directly onto the locusts, and (9) the difficulty in predicting outbreaks given the lack of periodicity of such incidents and the uncertainty of rainfall in locust areas.
Locust Emergency Response Toolkit
Countries and international agencies are in many cases unable to deal effectively with locust crises in their early critical stages. Consequently, assistance to reinforce the national capacities is often delayed, inadequate equipment is provided and the administrative and logistical back-up capacity on the ground is overwhelmed by the events. In this scenario, the Locust Emergency Response Toolkit (eLERT) provides operational support in order to improve the timeliness of locust emergency response. The eLERT is a dynamic and interactive online database whose main objective is to serve as reference, at both national and international levels, to respond more timely and effectively to the needs in a fast evolving crisis situation. It provides important information on critical aspects such as pesticides registered in the affected countries for locust control, technical specifications of recommended equipment, suppliers, standard contracts for aerial operators and consultants to reinforce the response capacities in the field, contact lists of important partners, rosters of consultants, etc. The eLERT should help people and agencies to act more effectively in coping with locust threats, thus preventing damage to the livelihoods of the rural population.
Calm;no threat to crops, maintain regular surveys and monitoring.
Caution;potential threat to crops, increased vigilance is required, control operations may be needed.
Threat;threat to crops, surveys and control operations must be undertaken.
Danger;significant threat to crops, intensive survey and control operations must be undertaken.
Forecast; small scale breeding will cause locust numbers to increase slightly in parts of Tharparkar, Nara and Cholistan as well as in the Lasbela area.