By Jesse Eastman
If grasshoppers have taken over your yard, then you understand how destructive their appetite for your beautiful flowers and vegetables can be. These voracious insects feed on a wide variety of plants, and due to their speed and mobility, many sprays are only marginally effective against them. If you choose to do nothing, you may be left with nothing more than the tattered remains of a few sad plants and the orchestral hum of hordes of fat, content grasshoppers. Just take a look at this comment posted on our facebook page:
This is a common problem in Colorado. Our environment tends to be favorable for grasshoppers, and additionally, this year’s early, dry spring has driven grasshopper populations sky high. According to the Colorado State University Extension Office, warm dry springs provide an optimal environment for the growth and development of grasshoppers. Many diseases that commonly limit grasshopper population only thrive in cooler wet weather, and we haven’t really experienced that this year. This means that grasshoppers haven’t either, which is bad news for our precious plants.
There are a few good control methods mentioned in the post above.
- Turn your garden soil: Most grasshoppers lay their eggs in the soil, so disrupting the eggs throughout the winter can help decrease the size of the larva hatch in the spring.
- Repellent plants: There are also several plants that seem to be somewhat effective in repelling these hungry bugs when planted as a barrier crop (use these as perimeter plants around your garden), although no formal studies have been done. These plants include cilantro, horehound, and calendula.
- Predators: Preying Mantis are another fantastic control, however with the size of the grasshopper population this year, you would need a terrifying army of mantises to keep pace. Other predators that eat grasshoppers by the ton include garter snakes, birds, including chickens and ducks, cats, and toads. Even spiders will eat grasshoppers, so don’t be afraid to let those web-spinners do their work!
A few other control methods that are good to bear in mind:
- If you have a border area to your yard, away from your gardens, where you can let the grass grow tall, leave it undisturbed. This gives the grasshoppers somewhere to live other than your garden. When the grass is short, they quickly move into the garden where tall plants provide greater cover from predators.
- Nosema locustae (NOLO Bait): This biological control causes an infection that exclusively harms grasshoppers. When used as long term control, it prevents grasshoppers from maturing, as it is most effective when grasshoppers are young, killing them within 2-3 days. More mature grasshoppers are not as prone to infection, and the NOLO Bait might take much longer to kill them, or may simply make them lethargic. When used year after year, this can be one of the most effective controls on the market today, and has the added benefit of not harming beneficial insects, pets, children, or plants.
- Standard pesticides: Standard chemical pesticides like pyrethrin/permethrin and carbaryl effectively kill grasshoppers. Bear in mind, though, that grasshoppers are highly mobile, so these sprays are less effective than the baits. Additionally, these sprays are broad spectrum, meaning they will kill pests as well as beneficial insects such as bees, lady bugs, and mantises.
Hopefully this helps you understand a little more about one of Colorado’s most frustrating pests. There are many ways to control the scope of their damage, and I encourage you to choose the method which gets that job done with the least amount of collateral impact.
For more resources and information on grasshopper control, check out these links: