Locust General Information
Animals and Pests
Rocky Mountain Locust
Control of the Desert Locust
Locust is the name given to the "swarming" phase of short-horned grasshoppers. They are six inches in length and the only invertebrates considered kosher. They breed rapidly under certain conditions and will become migratory. Locusts form bands as nymphs and swarm as adults.
Locusts can travel great distances, rapidly stripping fields and damaging crops. The swarming behavior is a response to overcrowding. It is triggered when their hind legs are increasingly stimulated. Several contacts per minute over a four hour period can induce the transformation into swarming.
The largest infestation of swarming locusts was the outbreak in 2004 by the Desert Locust in West and North Africa. Outbreaks occurred where there was a great increase in rain, during which time the locusts breed more rapidly. By 2004, swarms began to form and move into agricultural areas damaging crops. As the year progressed, swarms migrated over the entire continent causing devastation. By November they appeared in Northern Egypt, Jordan and Israel for the first time in 50 years. The lack of rain and cold weather in Northwest Africa slowed down development which allowed control agencies to stop the cycle in 2005.
Male and female locusts can be distinguished by looking at the ends of their abdomen. Males have a boat-shaped tip while females have two serrated valves that can be either together or apart. These help her in digging the hole where her egg pods will be deposited.
The migratory locust is the most widespread locust species. They use to be common in Europe but have died out and are currently found in Africa, Asia and Australia.
Migratory Locusts go through two phases: the solitary phase and the migratory phase. Solitary larvae are green or brown and adults are brown with green markings, depending on the vegetation it feeds on. Its wings are completely transparent. They often seek heated areas and colonize in steppes and savannahs with little or
no tree cover. When stimulated, they change to the migratory phase. Gregarious (or migratory) larvae are yellow with orange colors on their body covered by black spots. As adults they are brownish with yellow markings and are smaller than the solitary adults.
The red locust is found in the Sahara desert in Africa. They are also known as the
'criquet nomade' because of its seasonal movement and called the Red locust because of the color of its hind wings. The overall color of the red locust is beige and brown. They are never green.
Red Locusts have several clear brown bands on its body. Often mistaken for the bird locust, they seek moisture rich environments in seasonal flood plains and grassy lowlands. During swarming, they slowly fly with the wind during daylight hours.
The female Red Locust can produce 70-90 eggs that are laid at night in sandy soil.
Rocky Mountain Locust
The rocky mountain locust gets its name because of its habitat in the Rocky Mountains. They recently have expanded into the Great Plains. Swarms of this locust were last seen between 1873 and 1877, during which time they devoured everything from barley to buck weed and spruce trees to tobacco. They even ate the blankets farmers had put over their crops to protect them. Because of severe droughts, the crops collected sugar in their stalks which gave the locusts good food supply and the heat caused the insects to grow more quickly. Many farmers at the time moved because the rocky mountain locust wiped them out. During 1874 the swarm was recorded to be 1800 miles long and 110 miles wide.
This locust was last seen in Southern Canada in 1902. No one knows what happened to this insect, but concluded that their breeding grounds were destroyed by agriculture and the grazing of livestock. Preserved remains have been found in Grasshopper Glacier, Montana. Currently North America is the only populated continent without a major locust.
The desert locust has threatened agricultural production in Africa, the Middle East and Asia. The most dangerous of locusts, this locust is a pest because of its ability for swarms to fly rapidly over large distances. There are usually 2-5 generations per year. They live solitary lives until it rains.
The presence of rain causes the vegetation to grow and allows females to lay eggs in sandy soil. New vegetation provides shelter for newly hatched locusts to develop.
When the vegetation is grown close together, locusts have to group together to feed and such close contact can cause the insect legs to bump together. This stimulation causes them to change from solitary form to gregarious form, changing color in the process from green to yellow and black. Their bodies become shorter and they give off a scent that increases the swarming.
Under optimal conditions, swarms can form and invade countries as far north as Spain and Russia and south to Nigeria and Kenya and east to India and southwest Asia. Swarms can fly up to 2000 meters above sea level; any higher and itís too
cold for them to survive. Because of this they cannot cross tall mountain ranges and will not go into the rainforests of Africa or central Europe.
The Desert Locust has been reported to cross the Red sea and the Atlantic Ocean into the Caribbean. A single swarm can produce 40-80 million locusts.
Desert locusts consume leaves, flowers, and the stems of fruits and seeds. They also feed on rice, sugar cane, barley, cotton, fruit trees,
vegetables and bananas. Locust droppings are toxic and will spoil any food left uneaten. Plagues of the Desert Locust have occurred from 1926-1934, 1940-1948, 1949-1963, 1967-1969, and 1987-1989. The last swarm was located in Somalia and Eastern Ethiopia in September of 2007.
Control of the Desert Locust
The Desert Locust Information Service in Rome, Italy monitors the weather conditions and locust situation daily. Warnings are displayed on their website and in monthly bulletins. They are difficult to control because
of the remote areas and the under developed infrastructure of the areas they are found in. Natural enemies of the desert locust are parasitic wasps and flies, predatory beetle larvae, birds and reptiles.