Are Locusts Beneficial or Harmful Insects? Understanding the Pros and Cons of Locusts in One Article

Locusts, also known as grasshoppers and by other names, are the collective term for insects of the family Acrididae in the order Orthoptera. They are distributed across grassland and desert regions of the tropical and temperate zones worldwide. There are more than 10,000 species worldwide, and over 1,000 species in China. Among them, the migratory locust (Locusta migratoria manilensis) has the widest distribution and causes the most severe damage in China. Let us take a look below at whether locusts are beneficial or harmful insects!

Are locusts beneficial or harmful insects?

Locusts are agricultural pests. Locusts are an important component of agricultural, forestry and pastoral ecosystems. Many harmful locust species can cause varying degrees of damage to agriculture, forestry and animal husbandry. There are already more than 10,000 species of locusts worldwide, of which about 300 species can cause harm to agriculture, forestry and animal husbandry. Locusts can occur everywhere in the world except Antarctica and the regions of the Eurasian continent north of 55°N latitude. The area where locusts occur year-round worldwide reaches 46.8 million square kilometers, and 1/8 of the global population is frequently affected by locust plagues.

What harm do locusts cause?

Locusts mainly include migratory locusts and non-migratory locusts. Non-migratory locusts have a wide food range and can feed on the leaves, tender stems, flower buds and young fruits of wheat, rice, millet, corn, beans, tobacco, reeds, vegetables, fruit trees, forest trees and weeds, biting the leaves into notches or holes. When outbreaks occur, they can strip crops to bare stalks or eat them completely, causing serious economic losses. Migratory locusts mainly feed on plants of the grass family (Poaceae) and sedge family (Cyperaceae), with reeds, barnyard grass and red grass being their favorite weeds. Among cultivated crops, they also like to eat wheat, corn, sorghum, rice, millet, sugarcane and so on. When outbreaks occur and food is scarce, they can also damage crops such as cotton, soybeans and vegetables.

Prevention and control of locust damage

1. Agricultural control: The main methods of agricultural control of locusts can be summarized into three types.

(1) Reduce food sources: Many species of locusts eat corn, wheat, sorghum, rice, millet and so on, but do not eat soybeans, alfalfa, fruit trees and so on. Therefore, in locust outbreak areas, planting as many soybeans, alfalfa, fruit trees and other forest trees as possible can help control locusts.

(2) Reduce habitat: Some locust outbreak areas have low-lying terrain. We can convert such plots into ponds for raising fish and shrimp. This can greatly reduce locust habitat and also effectively control locusts.

(3) Reduce egg-laying sites: Some locusts like to lay eggs in dry, bare plots. Increasing the intensity of afforestation and planting trees, increasing the number of plants so that plant coverage reaches over 70%, will make such plots unsuitable for locusts to lay eggs, and can thereby reduce locust damage.

2. Biological control: There are currently three main biological control methods used for locusts.

(1) Protect and utilize natural enemies to control locusts, such as protecting frogs, lizards, birds, predatory beetles, parasitic wasps, parasitic flies and so on.

(2) Use biological pesticides to control locusts. The biological pesticides currently used to control locusts include locust microsporidia, Metarhizium anisopliae and azadirachtin, among others.

(3) Use grazing chickens and ducks to control locusts. Chickens and ducks also prey on locusts, and while controlling locusts they also increase agricultural production benefits.