What Do Locusts Eat?

What Do Locusts Eat?

A locust (family Acrididae) is a name often used when speaking about any insect in the order Orthoptera. For the most part, when you hear someone talking about locusts in North America, they’re talking about short-horned grasshoppers that tend to move together in swarms of great numbers. 

There are actually no longer any locusts in the United States, despite these insects being a type of short-horned grasshopper themselves. However, until the 1870s, locusts called the Rocky Mountain locust (Melanoplus spretus) were responsible for many farmers dealing with significant crop losses in the United States and Canada. 

While there are no locusts left in the U.S. or Canada, there are still grasshoppers. Sometimes, those are able to increase in number and cause a “plague,” which is when they move together in a swarm and destroy large sections of crops en masse. 


Locusts look like big grasshoppers because they are grasshoppers. Locusts, which are a kind of short-horned grasshopper, are herbivores that like to eat all kinds of plant life. They have four smaller front legs, two large back legs for jumping, and wings that extend just past their abdomen. They have two antennae, and locusts usually look brown or green in color. 

Locusts are a specific kind of swarming grasshopper that usually stays between .5 and 3 inches long. Rather than remaining solitary like other kinds of grasshoppers, locusts can become gregarious. During their gregarious phase (this is the swarming phase), locusts can become more colorful and want to feed and mate, coming together in a large swarm that can wipe out entire fields of crops. 

It’s important to note that locusts generally look like ordinary grasshoppers. When they’re not yet mature, they won’t have wings, so you might not give them a second glance. However, as they age, they will grow their wings and they could, if the conditions are right, move into the gregarious phase and begin to get ready to swarm. 

Locusts can move into the gregarious phase at any point in their youth. They can already be in the phase when they emerge from their eggs as non-flying nymphs, or they can convert to that phase later in life but prior to becoming an adult in around 24 to 95 days


Locusts, when hungry and ready to feed, will eat all kinds of plant life to fill themselves. During the gregarious phase, locusts have the potential to devour entire hectares of farm crops. 

During the swarming stage, locusts can eat things like:

  • Soft greens
  • Grasses
  • Natural foliage
  • Herbs
  • Spinach
  • Tomatoes
  • Beets
  • Onions
  • Carrots
  • Potatoes
  • Wheat
  • Corn
  • Apples
  • Green beans
  • Pumpkins

…and many other kinds of fruits, vegetables, and plants. 

The reality is that if a locust swarm is coming, no one’s plants are safe. While locusts might have a preference for something like soft fruits or vegetables, they will also dig into drier grasses or greenery. 


Locusts as Carnivores: Locusts usually get all the water they need by eating the plants and crops all around them. However, in the event that there isn’t enough water for them (and no water source, like a lake, is nearby), they will actually begin to cannibalize each other. So while locusts are herbivores, they will become carnivorous when fighting for survival.



If you’ve ever heard about locust swarms and plagues, you know why they’re so upsetting. They come in droves across the sky and descend on fields and grasslands. How, though, do they know where to go? 

This is where things get a little interesting. When solitary locusts are forced to live close together when it’s hot and there are dry spells, they’ll develop into their gregarious phase thanks to the release of serotonin (a neurotransmitter) that makes them more sociable. As they adapt to the new conditions, that same serotonin pushes them to have a more varied appetite than usual. They’ll also be primed and ready for quick movement when it comes time to swarm.

It isn’t during a dry spell that locusts are likely to be on the move. Instead, they take off as soon as the rain falls. When the soil becomes moist and plants perk back up and start growing, the locusts start eating in their original habitat. They grow, and their crowding gets worse. Then, they go on the hunt for food. 

When finding food as a swarm, some locusts can move up to 81 miles or more in a day. They really don’t have to have a set destination because they can travel such a long distance. Swarms have been known to go from areas like northwest Africa to Great Britain as well as to travel across waterways like the Red Sea

When the traveling locusts smell grass or crops, they descend. They can also use their antennae to investigate possible food sources, and then they start dining.

The problem with locusts is that they can eat so much. A single swarm can be made up of 40 to 80 million locusts per half-square mile and be up to 460 square miles in size. When they land and start chomping down, a swarm that size could eat over 423 million pounds of crops in a single day. 

To put that in perspective a bit, consider this: an average American will live to be 78.8 years old, and they will eat around 73,646 pounds of food in that time. In a single day, a swarm of locusts can eat as much as approximately 5,743 people eat in their entire lifetimes. 


Cancer-detecting Locusts? Locusts have an amazing sense of smell. Studies have shown that locusts can actually tell the difference between cells that do or do not have cancer. This shows that locusts are highly sensitive to changes in certain volatile organic compounds (VOCs) and how they smell when someone exhales. 



The main thing that attracts locusts is vegetation. These insects are hungry, and they’ll fly as far as they have to for the food they need to survive. 

When it rains and there is a great source of food, they will start looking—and smelling—for dinner. Some people, like those in Africa, are now trying to plant “bait” crops, like Mexican marigolds, to encourage the locusts to land on the borders of their farmlands. By doing that, the farmers have a better opportunity to stop the locusts before they destroy much-needed crops. 


The good news about locusts is that you’re unlikely to have a problem with them in the United States. The only locust that was a common swarmer in the U.S. is now extinct. However, that doesn’t mean that you might not have a problem with other outdoor pests.

If you have unwelcome insects or other critters that are making it hard to enjoy your yard, let us know. We’re here to help you get rid of them and get your life back to normal. Call us at Joshua’s Pest Control, and we’ll get you a free quote. 


Author Bio

Courtney Enzor has worked in the pest control industry for about a decade. From helping you build a fly trap to giving you the best tips for identifying various bugs, she loves answering all your pest-related questions and sharing her pest-related expertise through writing. At the end of the day, she hopes her content will help people avoid mishaps and keep families happy and healthy!