Grasshoppers are herbivores that feed on a variety of plants. For those cultivating plants, the direct answer to whether grasshoppers are beneficial is that they are overwhelmingly considered agricultural and garden pests. While they have a place in the broader environment, their presence in a managed garden space often leads to significant crop destruction.
Understanding Grasshopper Damage in the Garden
Grasshoppers are generalist feeders that consume many different plant species. They inflict characteristic ragged holes on leaves and flowers, often consuming entire sections of foliage. They display a distinct preference for young, lush green plants, including common garden vegetables such as lettuce, carrots, beans, and sweet corn.
The severity of the damage tends to increase as the season progresses, with adults becoming more voracious and mobile in mid to late summer. A single female grasshopper can lay around 100 eggs in the soil during the fall, which hatch into small nymphs the following spring. Both the wingless nymphs and the adult grasshoppers feed, but the damage escalates when surrounding grasslands dry out or are harvested.
Grasshoppers will then migrate en masse into irrigated areas, treating the garden as a green oasis and causing rapid defoliation. In severe outbreak years, their feeding is indiscriminate, sometimes extending beyond plants to materials like window screen, paint, or wooden fence posts when other forage is scarce. This migratory behavior can quickly overwhelm a small, unprotected garden space.
Grasshoppers’ Ecological Niche
While they are detrimental to cultivated plants, grasshoppers fill a significant and complex role in the natural ecosystem. They function as primary consumers, influencing plant community structure by keeping certain species in check, which can help promote ecological diversity. This herbivory can also accelerate nutrient cycling in the soil by breaking down plant matter more quickly than natural decay.
Grasshoppers are a major food source, forming a substantial link in the food chain for a wide range of predators. Birds, reptiles, small mammals, spiders, and even some predatory insects like robber flies rely heavily on grasshoppers for sustenance. Their bodies and waste also contribute to soil health, as their nitrogen-rich remains and droppings enrich the growing medium when they decompose.
Their primary interaction with plants is destructive feeding rather than nectar collection or pollen transfer. Any perceived ecological benefit is limited to unmanaged, natural habitats and does not translate into a reason to tolerate them in a vegetable garden.
Practical Strategies for Population Management
Effective grasshopper management in a garden setting requires an integrated approach focusing on prevention and early intervention. Since most grasshoppers overwinter as eggs laid in the topsoil of undisturbed areas, a cultural control strategy is to lightly till or cultivate weedy borders and fence lines in the late fall or early spring. This action disrupts the egg pods and exposes them to harsh weather conditions or predators.
Monitoring for the tiny nymphs as they emerge in the spring is a proactive measure because they are less mobile and more susceptible to treatment than adults. Physical barriers are a highly effective, non-chemical control for protecting small, individual plants or garden beds. Using fine insect netting or even metal window screening is recommended, as grasshoppers can chew through standard cloth row covers.
Biological control options are also available, notably the use of a natural protozoan called Nosema locustae. This single-celled organism is mixed into a wheat bran bait, which the grasshoppers consume. It causes a disease that reduces their feeding, slows their development, and eventually leads to death, with the best results seen when applied to young nymphs in their hatching areas.
If populations are extremely high, chemical control may be necessary, but this should be targeted and used sparingly, especially in edible gardens. Low-toxicity options like pyrethrins can be applied, but the high mobility of grasshoppers means that re-application may be necessary every few days. Focus the application on the perimeter of the garden and the surrounding weedy areas where new grasshoppers are moving in.