Grasshoppers are chewing pests that quickly cause extensive damage to gardens and agricultural crops. They possess strong mandibles, allowing them to consume large quantities of foliage. A large population can defoliate entire plants, leaving them too weak to survive or produce a harvest. Growers can protect plants using physical barriers, targeted organic treatments, and long-term habitat modification strategies.
Physical Barriers and Exclusion Techniques
Physical exclusion is the most straightforward method for shielding vulnerable plants from grasshopper feeding. This involves creating a sealed barrier that the pests cannot penetrate, which is especially helpful for young or high-value plants. Floating row covers, made from lightweight spun-bonded fabric, are effective because they allow light, air, and water to pass through while blocking insect entry.
A mesh size around 1.0 mm (approximately 25–40 mesh) is sufficient to prevent grasshopper access. The barrier must be installed before the pests become active, and the edges must be sealed completely to the ground. Securing the material by burying the edges in soil, or weighing them down with rocks, boards, or sandbags, prevents grasshoppers from crawling underneath.
For taller plants or those requiring more durable protection, fine metal window screening or framed cages can be used, as grasshoppers can chew through some cloth materials. If using exclusion methods on plants that require insect pollination, such as squash or cucumbers, the covers must be temporarily removed during the morning hours when pollinators are most active to ensure proper fruit set.
Natural and Organic Direct Controls
When grasshoppers are already present, direct-action organic controls can target the pests with minimal environmental impact. Diatomaceous Earth (DE) is a powder made from the fossilized remains of diatoms, which works mechanically rather than chemically. The microscopic, sharp edges of food-grade DE scratch the insect’s protective exoskeleton, causing desiccation and death.
For DE to be effective, it must be applied as a fine, dry dust directly onto the foliage and around the plant base where the grasshoppers crawl. It loses potency when wet, so reapplication is necessary after rain or heavy dew. While DE is effective, it is non-selective and should be applied carefully to avoid covering blooms where beneficial pollinators may land.
Another organic option is insecticidal soaps or neem oil sprays, which are most effective against young grasshopper nymphs due to their softer exoskeletons. Neem oil contains the active compound azadirachtin, which acts as a feeding deterrent and growth disruptor, slowing pest development. These liquid treatments must be applied directly onto the grasshoppers or the foliage they consume, ideally in the early morning or late evening to prevent leaf burn from the midday sun.
For larger infestations, a biological control using bran-based baits containing the microsporidian protozoan Nosema locustae can be highly effective. This natural pathogen is mixed with wheat bran, which grasshoppers are attracted to and readily consume. Once ingested, the protozoan infects the gut, causing the grasshoppers to become lethargic, reduce their feeding, and eventually die. The disease is contagious and spreads through the population, especially when healthy grasshoppers cannibalize infected ones. Application is most effective early in the season when grasshoppers are in their young nymph stages and still concentrated in their hatching areas.
Habitat Modification and Long-Term Prevention
Long-term management focuses on disrupting the grasshopper life cycle to reduce the population before it becomes a problem. Female grasshoppers lay their eggs in the soil in late summer and fall, typically in undisturbed, weedy areas, ditches, or untilled fields surrounding the garden. The eggs are encased in a protective pod and overwinter in the upper few inches of soil, hatching into nymphs the following spring.
Tillage operations in these preferred egg-laying sites, performed in the late fall or early spring, can significantly reduce the next generation. Turning the soil exposes the egg pods to freezing temperatures, desiccation, and predation from birds and blister beetle larvae, which can destroy up to 80% of the eggs in localized areas. Eliminating weedy growth in and around the garden border also removes the primary food source and shelter for newly hatched nymphs, forcing them to move or starve.
Encouraging natural predators provides a self-sustaining form of control. Birds such as bluebirds, sparrows, and meadowlarks are voracious consumers of grasshoppers, particularly the younger nymphs. Providing a source of water and safe nesting sites, free from domestic pets, helps attract and maintain bird populations near the garden. Other natural enemies include ground beetles, robber flies, and parasitic wasps, which can be encouraged by maintaining year-round habitats like perennial borders and providing insectary plants that supply nectar and pollen.