Grasshoppers are common garden pests that can quickly devastate plants by chewing through leaves and stems. Successful management requires a multi-faceted strategy that combines physical protection, biological controls, targeted treatments, and environmental adjustments. By implementing several of these natural methods in an integrated approach, gardeners can protect their crops and reduce grasshopper populations without resorting to harsh chemicals.
Physical Barriers and Direct Removal
Protecting vulnerable plants starts with physically blocking the grasshoppers from reaching them. Fine-mesh floating row covers or insect netting provide a highly effective physical barrier. Secure the edges of the netting tightly to the ground, preventing grasshoppers from walking underneath. Since grasshoppers can chew through softer cloth, a finer mesh or metal screening may be a more durable option for high-value plants.
Another direct approach involves hand-picking the insects, which is most effective for smaller infestations. Grasshoppers are cold-blooded, making them sluggish and easier to catch during the cooler hours of the day, specifically in the early morning or at dusk. Captured grasshoppers can be dropped into a bucket of soapy water, which quickly drowns them.
Simple traps can also assist in collection, utilizing the grasshopper’s attraction to sweet substances. A basic molasses trap can be made by filling a small container with a solution of one part molasses to ten parts water. Placing a film of oil on the surface of the liquid can help ensure the insects drown, while also deterring beneficial insects like bees from the trap.
Utilizing Biological Controls and Predators
Introducing or encouraging natural enemies provides a sustainable, long-term solution. One specific biological control is Nosema locustae, a naturally occurring microsporidium protozoan sold commercially as Nolo Bait. Mixed with a wheat bran bait, it infects the grasshopper’s fat bodies, causing a debilitating disease that leads to lethargy, reduced feeding, and death.
The bait is most effective when applied early in the season as the grasshoppers emerge in their nymph stage, which is when they are most susceptible to the infection. Infected grasshoppers can spread the disease to others through cannibalism, creating a self-perpetuating control cycle. Nosema locustae is non-toxic to humans, pets, livestock, and beneficial wildlife, making it a safe option for widespread application.
Attracting larger predators can also significantly reduce grasshopper populations. Domestic fowl, particularly chickens and guinea fowl, are voracious grasshopper eaters. If poultry is used, supervise them or use temporary fencing, as they may damage garden plants while foraging. Birds, robber flies, ground beetles, and parasitic wasps also prey on grasshoppers. Providing water sources, nesting sites, and diverse flowering plants encourages these beneficial species.
Non-Toxic Topical Treatments
Topical treatments offer a way to target grasshoppers directly on plants using natural, non-chemical ingredients. Diatomaceous Earth (DE) is a fine powder made from fossilized diatoms that acts as a mechanical insecticide. When grasshoppers come into contact with the powder, its microscopic sharp edges abrade the insect’s exoskeleton, causing it to rapidly lose moisture and die from dehydration.
For DE to remain effective, it must be applied as a fine dust and kept dry, requiring reapplication after rain or heavy dew. Apply it to the foliage, including the undersides of leaves, ensuring the grasshoppers crawl through it. All-purpose flour is another simple dusting method that gums up the grasshopper’s mouthparts, preventing feeding, but it must be reapplied frequently.
Homemade sprays can also deter or eliminate grasshoppers through contact or as an anti-feedant. Prepare a neem oil solution by mixing two quarts of warm water with a half-teaspoon of mild liquid soap and slowly adding three teaspoons of pure neem oil. The soap acts as an emulsifier, allowing the oil to mix. Neem oil deters feeding and disrupts the grasshopper’s growth and reproduction cycle.
A strong garlic spray can be used as a general repellent, taking advantage of the grasshopper’s sensitivity to pungent odors. To create a simple garlic preparation, blend two bulbs of garlic with ten cups of water, boil the mixture, and let it steep for at least eight hours. The concentrated liquid should then be diluted with three parts water before being sprayed liberally onto the plants.
Environmental and Habitat Management
Long-term grasshopper control depends heavily on disrupting their life cycle, which begins with eggs laid in the soil. Female grasshoppers deposit egg pods (20 to over 100 eggs) in the top two inches of undisturbed soil, typically in grassy areas, ditches, or field borders. Tilling the soil in late fall or early spring exposes these egg pods, causing them to desiccate or be consumed by predators.
Weed management is a simple but effective preventative measure, as grasshoppers use tall weeds as both shelter and a food source. Maintaining a clean area around the garden reduces the number of attractive habitats for both egg-laying and feeding. Grasshoppers are often drawn to lush, green growth, which means that overly irrigated or fertilized plants can become targets.
A strategy known as trap cropping involves planting a border of plants highly attractive to grasshoppers away from the main garden area. Tall grasses, alfalfa, or even certain grain crops like millet can serve as a sacrificial greenbelt, diverting the pests as they migrate from drier areas. This localized feeding area can then be targeted for more intensive control methods, concentrating the effort and protecting the primary crops.