Grasshoppers can be devastating agricultural and garden pests, quickly consuming foliage and jeopardizing harvests during warm, dry periods. Effective control requires understanding options across a spectrum of impact, moving from preventative cultural practices to targeted treatments. This evaluation compares physical barriers, low-toxicity sprays, and powerful chemical or biological controls to help gardeners intervene effectively against grasshopper infestations.
Proactive Garden Management and Physical Barriers
Cultural practices make the garden less attractive to egg-laying females. Grasshoppers deposit egg pods in untilled, weedy areas like fence lines or ditches. Tilling the soil in late fall or early spring exposes these overwintering egg pods to weather and predators, reducing the number of nymphs that hatch the following season.
Physical exclusion offers the most reliable, non-chemical defense for vulnerable plants. Floating row covers or fine mesh netting draped over hoops create a physical barrier. Secure the edges firmly to the ground to prevent pests from crawling underneath. For high-value plants, protective cones made from aluminum window screening can withstand chewing.
Low-Toxicity Spray Options
For low to moderate grasshopper populations, several low-toxicity sprays and dust applications are effective, especially when targeting young nymphs. Diatomaceous Earth (DE) is a mechanical control, a finely ground sedimentary rock. When dusted onto plants, the sharp, microscopic DE particles scratch the grasshopper’s waxy outer layer, causing dehydration and death.
Botanical oils, such as neem oil, work as a repellent and an insect growth regulator. The active ingredient azadirachtin disrupts the grasshopper’s feeding and molting processes. Neem oil is most effective against nymphs, acting as an antifeedant that causes them to starve.
Homemade sprays containing irritants like garlic or chili peppers can deter grasshoppers due to the pungent scent. Insecticidal soaps, which are potassium salts of fatty acids, are contact treatments. These soaps require direct contact to dissolve the insect’s protective outer membrane, leading to desiccation. Low-toxicity sprays require thorough, repeated application, especially after rainfall, to maintain effectiveness.
High-Impact Treatment Solutions
When grasshopper numbers reach overwhelming levels, high-impact solutions are necessary for rapid population reduction. Targeted chemical control involves using baits impregnated with insecticides like carbaryl or synthetic pyrethroids. Carbaryl is commonly formulated into wheat bran baits, which grasshoppers readily consume, providing a quick-kill effect.
These insecticidal baits offer a more selective treatment than broad-spectrum sprays, as the poison is ingested by foraging grasshoppers. For an environmentally focused solution, the biological control agent Nosema locustae is a microsporidian parasite incorporated into a wheat bran bait. This protozoan is non-toxic to humans, pets, and beneficial insects, specifically targeting grasshoppers and crickets.
Nosema locustae infects the grasshopper’s gut after ingestion, causing a debilitating disease that leads to reduced feeding and eventual death over several weeks. It is most successful when applied early in the season to young nymphs. The disease can spread through cannibalism, offering a persistent control that reduces the population’s ability to reproduce.
High-impact chemical sprays are also available for immediate knockdown. These require careful adherence to label instructions to minimize environmental impact. They are best used only for severe, localized outbreaks.
Choosing the Right Strategy for Your Infestation
Effective grasshopper control is an integrated strategy tailored to the severity of the infestation. For prevention, cultural practices like fall tilling and physical barriers offer non-toxic, long-term protection.
If the population is small or moderate, low-toxicity sprays like neem oil or Diatomaceous Earth provide sufficient intervention. When large numbers of grasshoppers migrate, high-impact solutions become necessary.
The use of Nosema locustae bait is preferred for its targeted biological action. A selective carbaryl bait provides the fastest knockdown for overwhelming infestations. The decision rests on the pest density, the size of the area, and the gardener’s tolerance for environmental risk.