Locust

Locust is the name given to several species of grasshopper belonging to the family Acrididae, which under specific conditions can change from a solitary lifestyle to form large groups that migrate together. Locusts differ from other grasshoppers in having two distinct states: a solitary phase and a gregarious phase. The shift between these two states affects coloration, body shape, and behavior.

When heavy rains fall in arid regions, vegetation and pasture increase, enabling locusts to breed rapidly. High locust density leads to sustained physical contact, which triggers the shift to the gregarious phase. The resulting swarms can travel long distances following wind patterns and consume the plants, crops, and pasture they encounter.

Common species

The Desert locust (Schistocerca gregaria) has the greatest impact on East Africa, the Middle East, and southwestern Asia. Other species include the African migratory locust (Locusta migratoria), as well as species found in Australia and the Americas. Each species occupies a particular range and has breeding seasons tied to rainfall patterns.

Life cycle

Female locusts lay eggs in the soil, depositing them in groups called egg pods. After hatching, wingless young called hoppers emerge and move along the ground. Following these stages, the locust develops into a winged adult capable of flight. The hopper stage is important for control efforts, because the insects cannot yet fly and can therefore be targeted in a specific location.

Impact on agriculture

A locust swarm can consume in one day an amount of food equal to its own weight. When swarms descend on agricultural land or pasture, they can reduce crop yields and livestock forage, affecting the food security of farming and pastoral communities. The severity of damage depends on swarm size, the season in which the crops are affected, and the locust migration patterns.

Prevention and management

Agricultural agencies in affected countries and international bodies such as FAO operate an early warning system that monitors rainfall, vegetation cover, and soil moisture. The most common interventions are pesticide application by ground spray or aircraft, and biological control methods based on fungal agents. Coordination between neighboring countries is also important, because swarms do not respect borders.