FAQs

What is a Desert Locust?

What is a Desert Locust?

The Desert Locust is one of about a dozen species of short-horned grasshoppers (Acridoidea) that  in response to environmental factors can quickly form dense swarms of adults or bands of hoppers (young wingless locusts).

What makes locusts distinctive?

What makes locusts distinctive?

Locusts belong to a particular family of grasshoppers called Acrididae. They have the ability to change their behaviour and habits, and can migrate over large distances.

What countries are affected by the Desert Locust?

What countries are affected by the Desert Locust?

During quiet periods (known as recessions) Desert Locust are usually found only in 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 km2, consisting of some 30 countries.

During plagues, Desert Locust can spread over vastly larger areas, potentially as much as 29 million km2 and extending over or into 60 countries. In plagues like these, the pest can pose a threat to the livelihoods of one-tenth of the world's population.

Can locusts hurt humans?

Can locusts hurt humans?

Locusts do not attack people or animals. There is no evidence to suggest that they carry diseases that could harm humans.

What harm do locusts do then?

What harm do locusts do then?

Desert Locust can eat massive quantities of vegetation – wild plants, shrubs, trees and grass, resources that are critical for the health and survival of millions of pastoralist people in Africa, whose animals depend on them for forage. But also, food crops and fruit trees. The locusts in effect steal food from people's mouths, and from livestock that pastoralists depend on to survive. This can badly erode the food security of affected communities – and leave people stripped of household assets like seeds or animals. For more on locust’s consumptive capacity, see below.

Where are the Desert Locust now?

Where are the Desert Locust now?

For up to date information, visit the FAO Desert Locust watch website, which is regularly updated as the situation evolves.

I am hearing about swarms in West Africa, China, and other places. What is happening there?

I am hearing about swarms in West Africa, China, and other places. What is happening there?

Media accounts (in early 2020) have sometimes mis-reported the presence of Desert Locust or confused Desert Locust with other species. There are currently no swarms in West Africa (e.g. Ghana). Sightings in Botswana, Namibia and South Africa are of different species, not Desert Locust; they do not present the same threat as Desert Locust. Governments in these countries are capable of dealing with them. There is no Desert Locust risk to China, which is outside the natural range of Desert Locust. China does experience Asian Migratory Locust swarms and is well equipped to deal with them. Sightings of locusts on Spain’s’ Canary Islands are of an indeterminate species, not Desert Locust.

How big are the swarms? How many locusts are there in a swarm?

How big are the swarms? How many locusts are there in a swarm?

The swarms can be anything from under one km2 to several hundred km2. There can be from 40 million to 80 million adult Locusts in each square kilometre of a swarm.

Is this an outbreak, an upsurge, or a plague?

Is this an outbreak, an upsurge, or a plague?

Desert Locust infestations are identified in a sequence of increasing severity as follows: recession (calm); outbreak; upsurge; plague (maximum intensity and scope). The rankings depend on the magnitude and geographical scale of the infestations.

At the moment, the situation in East Africa is not at plague level. It is an upsurge. But it could become a plague if control operations are not adequate and weather favourable to breeding occurs.

The last time Somalia and Ethiopia saw an upsurge comparable to the current one (2020) was 25 years ago. Kenya and Uganda have not seen an upsurge at this scale for 75 years. Plagues tend to occur intermittently, rather than at specific intervals. Plagues of Locusts have been reported since Pharaonic times in ancient Egypt, but more recently in 1926-1934, 1940-1948, 1949-1963, 1967-1969 and 1986-1989.

How much food can a Desert Locust eat?

How much food can a Desert Locust eat?

An adult Locust can consume roughly its own weight, about 2 grams, in food every day. A 1 km2 size swarm of 40 million locusts could eat the same amount of food in one day as about 35 000 people. This is based on a person eating an average of 2.3 kg of food per day, according to the USDA.

To provide some perspective: A swarm the size of Paris could eat the same amount of food in one day as half the population of France; one the size of New York City could consume in one day the same as everyone in New York and California combined; one the size of Rome can eat the same amount of food as everybody in Kenya; one the size of Sydney (Australia), the same amount of food in one day as all of Australia eats in 1.5 hours.

How much land is currently affected in East Africa, how much of that area has been treated by governments so far?

How much land is currently affected in East Africa, how much of that area has been treated by governments so far?

Precise estimates are impossible to come by because the areas are vast, many of which are remote and some are insecure. In addition, the swarms are constantly shifting from place to place. Tens of thousands of hectares have been treated by air and ground teams.

For latest figures: http://www.fao.org/emergencies/resources/maps/detail/en/c/1257519/

How much damage have the locusts done?

How much damage have the locusts done?

Reports of crop damage continue to come in from Ethiopia, Kenya, Somalia, but firm numbers on damages and losses cannot yet be reliably ascertained. Assessments are underway to gain a clearer picture of damages to crops as well as to forage vegetation crucial to pastoralists are underway. Because locusts reproduce very quickly and move rapidly, such numbers are always a moving target. But Desert Locust biology is a known; their destructive potential on crops and forage is clear. Just a 1 square km swarm has the potential to eat as much food in 1 day as 35,000 people could. In a worst case scenario, a farmer might see their entire crop destroyed, i.e., 100% losses.

What is the role of FAO in locust control, generally?

What is the role of FAO in locust control, generally?

FAO operates a centralized Desert Locust information service to provide updates to all affected countries and give timely warnings and forecasts to those countries at risk of invasion. All Locust-affected countries transmit data to FAO, which in turn analyses this information together with weather and habitat data and satellite imagery. FAO can then assess the ongoing Locust situation, provide forecasts up to six weeks in advance, and issue ad-hoc warnings. FAO prepares monthly bulletins and periodic updates summarizing the situation, forecasting migration, and breeding on a country-by-country basis.

FAO also provides training, undertakes field assessment missions, and coordinates survey and control operations, as well as assistance during locust upsurges and plagues.

What is being done to combat this current upsurge in East Africa?

What is being done to combat this current upsurge in East Africa?

FAO has designated the situation as one of its highest corporate priorities. FAO experts and emergency resources have been surged to the field. FAO is working with the governments of affected countries at the national and sub-national levels, as well as with partners and stakeholders in the region, to carry out control operations. Spraying the swarms is currently the only viable method of swarm control. This is a multi-stakeholder operation.

FAO is also seeking to mobilize international funding to support the deployment of experts and procure equipment. FAO's initial response plan (30 Jan) was for 70M USD for immediate needs. That was upgraded to 138M USD due to expanding needs. 

For more information on the FAO appeal for rapid response and anticipatory action in the Greater Horn of Africa, click here.

Who carries out locust control operations?

Who carries out locust control operations?

Locust survey and control are primarily the responsibility of national Ministries of Agriculture in affected countries. There is a regional locust organization in Eastern Africa that assists with aerial control operations. During times of outbreaks and plagues, external assistance from the donor community and other international organizations like FAO is usually required.

FAO encourages only properly trained and equipped teams to undertake control operations against Desert Locusts, and not communities or farmers. FAO provides comprehensive training on all aspects of locust control. Whenever possible, FAO actively encourages countries to use biopesticide, especially in sensitive areas such as near water bodies, national parks, grazing areas with animals, and in habitations.

How are pesticide risks managed during control activities?

How are pesticide risks managed during control activities?

Chemical pesticides used in locust control can pose risks to human and animal health. If handled properly and used in accordance with best practices, these risks are manageable.

A range of partners working on Desert Locust management – including governments, FAO and other organizations such as WHO, and UN Environment Programme – have developed standard operating protocols to guide the planning and execution of control campaigns in order to safeguard human, animal and crop health.

Only substances that are legally registered and approved for locust control by national authorities are used. Governments typically adhere to internationally agreed standards to establish national rules. Banned pesticides are never used.

Precise targeting and close monitoring of operations allow for the safest possible application of pesticides. Spraying must be applied to the locust itself and not generally to vegetation -- inhabited areas, beehives and grazing animals are carefully avoided. Monitoring spraying to ensure safety is as important a part of a control operation as the spraying itself.

The minimum volume of pesticide possible is applied.

Only well-trained and properly equipped teams undertake control operations, not farmers.

Ground and aerial control operations always abide by appropriate precautions, including the use of protective clothing and masks and correct application protocols.

National, regional and local authorities inform communities in advance regarding control locations and precautions they should take. At a minimum, livestock are  moved out of any areas where spraying is to occur and be kept out of such areas until authorities say otherwise. Communities are advised to avoid going to treatment zones as spectators but rather stay away, indoors if possible.

Withholding periods – the minimum period of time that must elapse between the last pesticide application and access to the treated area – are well-established by national authorities and communicated to communities.

As a precaution, people are warned not to consume treated locusts or animals that may have consumed them. Children are told never to touch dead locusts.

There are alternatives to chemical pesticide that can be effective. When possible, FAO encourages countries to use them (see biopesticide, below).

Is there a threat to any other parts of Africa? Are swarms going to invade more areas?

Is there a threat to any other parts of Africa? Are swarms going to invade more areas?

At the moment, there is no imminent threat to regions in Africa outside of East Africa. Contrary to some media reports, there is no locust problem in West Africa. However, it is essential to tackle the swarms now to avoid them spreading further. Desert Locust activity along both sides of the Red Sea, and in Southwest Asia (Iran, India, Pakistan) is also reason for vigilance. For up to date information on the global situation: http://www.fao.org/ag/locusts/en/info/info/index.html

How do locusts move?

How do locusts move?

Desert Locusts usually fly with the wind at a speed of about 16-19 km/h. Swarms can travel up to 130 to 150km or more in a day. Locusts can stay in the air for long periods. For example, locusts regularly cross the Red Sea -- a distance of 300 km.

In the past, there have been some spectacular and very long distance swarm migrations, for example from North-West Africa to the British Isles in 1954 and from West Africa to the Caribbean, a distance of 5,000 km in about ten days in 1988.

As Desert Locusts increase in number and become more crowded, they change their behaviour from that of acting as an individual (solitarious) insect to that as acting as part of a group (gregarious). The appearance of the locust also changes: solitary adults are brown, whereas gregarious adults are pink (immature) and yellow (mature). Solitary Desert Locust adults usually fly at night, whereas gregarious adults (swarms) fly during the day. Up until 1921, it was thought that the Desert Locust was actually two different species for this reason.

How can locusts be controlled?

How can locusts be controlled?

At present the primary method of controlling Desert Locust swarms and hopper bands is with mainly organophosphate chemicals applied in small concentrated doses (referred to as ultra-low volume (ULV) formulation) by vehicle-mounted and aerial sprayers and to a lesser extent by knapsack and hand-held sprayers. It is important to carry out effective control methods, such as spraying, early enough to curtail the surge in population.

Are there any other (non-chemical) methods other than pesticides that can be used to control the spread of locusts?

Are there any other (non-chemical) methods other than pesticides that can be used to control the spread of locusts?

There are methods but not for swarms of this magnitude. The best way to control the current upsurge is through effective aerial and ground spraying.

Extensive research is in progress on biological control and other means of non-chemical control of Locusts. The current focus is primarily on pathogens and insect growth regulators. Thus far, control by natural predators and parasites is limited since Locusts can quickly migrate away from most natural enemies. Although giant nets, flamethrowers, lasers and huge vacuums have been proposed in the past, these are not in use for Locust control.

Can bio-pesticides be used in Desert Locust control? What is the active ingredient?

Can bio-pesticides be used in Desert Locust control? What is the active ingredient?

Bio-pesticides present an ecologically acceptable and safe, low-toxicity alternative to conventional pesticides in Desert Locust control. The active ingredient is a microorganism, an entomopathogenic fungus Metarhizium acridum. It triggers an epidemic disease among the treated insects.

How do bio-pesticides work?

How do bio-pesticides work?

When Metarhizium acridum spores come into contact with the locust exoskeleton, they germinate on the cuticle and penetrate inside by pressure and enzymatic action. The fungus then multiplies inside the insect. The locusts are weakened and reduce feeding in three to four days, and die from seven days onwards. Under certain circumstances, the fungus can continue to produce spores in and on the dead locusts, which thus become a new source of contamination. Maximum mortality occurs two to three weeks after treatment. Both hoppers and adult locusts are susceptible to the bio-pesticide.

What are the advantages of using bio-pesticides?

What are the advantages of using bio-pesticides?

Metarhizium acridum is highly specific to locusts and grasshoppers. This means that it kills only these insects and does not negatively affect honeybees and other beneficial arthropods. It is not toxic to humans or animals such as birds, fish, reptiles, amphibians etc. The bio-pesticide requires standard Personal Protective Equipment (usually, a face mask and long-sleeved shirt are sufficient) and can be applied with the same ULV spraying equipment as the chemical pesticides. Contrary to chemical pesticides, the biopesticide can be applied to areas with water bodies.

What are the drawbacks of the bio-pesticide?

What are the drawbacks of the bio-pesticide?

Metarhizium acridum acts more slowly than the majority of chemical pesticides. It requires particular temperature and humidity conditions for storage and transportation. Spore viability should be checked before each application.

What is the best strategy to apply the bio-pesticide?

What is the best strategy to apply the bio-pesticide?

Due to the excellent ecotoxicological profile of Metarhizium acridum, it is a great fit for treating locusts in ecologically sensitive zones, such as nature reserves, wetlands or other areas with water bodies. The bio-pesticide is an appropriate tool for the preventive strategy to control the Desert Locust, particularly when it is necessary to treat initial, small groups of hoppers to prevent them from forming dense and huge hopper bands.

Can Locusts be detected by satellites?

Can Locusts be detected by satellites?

Weather satellites and other satellites used to monitor the environment cannot detect individual Locusts or swarms. Highly sophisticated satellites used by the military can indeed detect Locusts, but these images are not available for civilian use. Even if they were, it is unlikely that national and international Locust organizations would be able to interpret the hundreds of images that would be produced daily.

Are drones being used for locust early warning and preventive control?

Are drones being used for locust early warning and preventive control?

Typical drones available commercially are not likely to robust enough or sufficiently useful for locust operations. Therefore, FAO is researching and developing  a fixed-wing drone solution for long distance surveys of up to about 100 km while collecting data on the location of green vegetation and processing this imagery on board as a map. Rotary drones are also in development to map the extent of vegetation at a particular site, to spot locust concentrations and to spray infestations. National field teams could be equipped with drones to locate areas of green vegetation in the desert, search the areas for locusts, and treat them safely and effectively. The current upsurge offers an opportunity to put these new tools into practice for the first time. For more information, click here.

Can people eat locusts that have been killed by control activities? Why aren't people catching the locusts and eating them?

Can people eat locusts that have been killed by control activities? Why aren't people catching the locusts and eating them?

No. Locusts that have been killed by pesticides should not be consumed under any circumstances as they may still contain traces of pesticides.

In the context of the ongoing Locust upsurge and the control campaign to contain the threat, no one should eat any locusts, living or dead. Pesticide does not always kill the locusts immediately.

Even if these safety issues were not a factor, the notion of catching locusts in nets is not a realistic response to the problem. One of the swarms spotted in Kenya in January 2020 measured 40km wide by 60km long.

Why are Desert Locust so difficult to control?

Why are Desert Locust so difficult to control?

There are many reasons why it is difficult to successfully combat the Desert Locust. Some of these are: (1) the extremely large area (16-30 million km2) 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 among affected countries; (8) the difficulty in organizing and implementing control operations in which the pesticide must be applied directly onto the Locusts; (9) the difficulty in predicting outbreaks given their lack of periodicity and the uncertainty of rainfall in Locust areas; and (10) the lack of reliable forecasts and advanced warning of cyclone and other severe weather that often trigger to Desert Locust outbreaks and upsurges.

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