Summary: Grasshoppers are known for their leaping ability and the chirping songs they create using their back legs and wings. They feed on plants, often causing damages to garden plants and agricultural crops.
Grasshoppers are a group of insects that are closely related to, but distinct from, crickets and katydids. Like crickets, grasshoppers have long, powerful hind legs that it uses for jumping. It can jump over twenty times the length of its own body. The grasshopper sometimes rubs one of its back legs against a wing to make a sound known as stridulation. The sound is similar to a cricket's chirp.
Grasshoppers have wings in their adult stage and are capable of traveling quickly over large distances. The ability to fly and its herbaceous diet of grasses and grain crops makes the grasshopper a serious agricultural pest. Under the right conditions, grasshopper populations can explode in size. The short-horned grasshopper actually undergoes a behavioral change as its population grows. The insects become agitated, massing in great numbers, eventually changing into a single migrating swarm known as locusts.
Grasshoppers like drier climates that receive from ten to thirty inches of rain per year. Heavy rains tend to kill non-flying nymphs that get stuck in the mud. Conversely, in areas prone to drought there is not enough vegetation to support grasshopper populations.
Grasshoppers can grow up to five inches in length, females being larger than males. They are normally green or brown, but other tropical species can be brightly, multi-colored. Green or brown grasshoppers use their coloring to avoid predators by blending in with their environment. Brightly colored grasshoppers use their coloration as a warning sign to predators that they do not taste good. Grasshoppers are a delicious food source for birds, rodents, spiders, and other insects. Even humans sometimes eat grasshoppers, cooking them lightly in oil to make them crispy.
Grasshoppers undergo simple metamorphosis. They lay their eggs in bare soil. The eggs hatch in the spring and the young grasshoppers, called nymphs, begin to feed on grass or other plant material. The nymphs cannot fly and undergo four or five stages, known as instars. Pesticide treatments often target the grasshopper when it is in its nymphal stage due to the grasshopper's vulnerability during this time.
The four species of grasshoppers that are agricultural pests in the United States are the differentiated, two-stripped, red-legged, and migratory species. These species are responsible for 90% of damage to crops caused by grasshoppers in the US. They are vulnerable to blanket sprays of chemical pesticides like Malathion, Permethrin and Cyfluthrin. The sprays should be applied while the grasshoppers are young nymphs. Best times to treat are often determined by natural indicators such as when lilacs bloom or by counting the number of warm days at the beginning of spring.
Other methods of grasshopper control include poisonous baits, the introduction of biological control agents like a fungus or protozoa parasite that attacks the grasshoppers but do not affect other species. Additional tools that farmers use to fight grasshopper populations are crop rotation, tilling soil that contains eggs and harvesting early. Any of these methods can help increase a farmer's crop yield. To eliminate grasshoppers during the planting season the farmers will sometimes leave a narrow strip of plants for the grasshoppers to feed on so they all congregate in one area where they are easier to treat.
Grasshoppers are not generally a problem in urban environments, but in more rural locations they can be a pest to garden plants. To prevent this some gardeners cover their plants with a floating row cover to keep the grasshoppers out. Another method is to spray the plants with hot pepper wax insect repellent that will not harm the plant, but makes them unpalatable to grasshoppers. Neem oil or insecticides that contain Neem can be used in a similar way.
If you raise chickens or guinea hens, these birds can be let loose in the garden to feast on a grasshopper buffet. All these methods are alternatives to using synthetic pesticides. However, sprays like Surround WP are also effective in keeping grasshoppers out of gardens. The pesticides should be sprayed at night when the grasshoppers are less active and less likely to run and hide.
One more interesting fact about grasshoppers is that they spit out a brown juice when they feel threatened. The juice might be a defense mechanism that protects them from ants. If you pick up a grasshopper and spits on you, don't worry. The expectorant is not harmful to people. It just tastes and looks bad to predators. Reminds me of some of my favorite baseball players.