Diatomaceous earth (DE) is a non-chemical method for controlling insects, including grasshoppers. This fine, powdery substance is made from the fossilized remains of tiny aquatic organisms called diatoms, which are rich in silica. When used correctly, DE can effectively manage grasshopper populations in a garden or yard, but success relies on proper application techniques and dry conditions.
How Diatomaceous Earth Kills Pests
Diatomaceous earth is classified as a mechanical insecticide, meaning it does not rely on chemical toxicity to kill insects. The powder works through direct physical action, making it impossible for pests to develop resistance over time.
The primary method of action is abrasion, where the microscopic, razor-sharp edges of the silica particles cut into the insect’s waxy exoskeleton. This outer layer is a protective barrier that regulates the grasshopper’s moisture levels. Once compromised, the powder begins the process of desiccation.
The powder is highly absorbent, drawing moisture and oils directly from the insect’s body. Desiccation causes the grasshopper to lose bodily fluids rapidly. Fatal dehydration occurs when enough moisture is pulled from the system, leading to death within hours or days after exposure.
Effective Application Techniques for Grasshopper Control
Achieving successful grasshopper control depends heavily on precise application due to their size and mobility. The powder must come into direct physical contact with the grasshopper’s body, particularly its joints and belly, to be effective. Simply dusting plant leaves is often not enough, as grasshoppers may feed without fully crawling through the substance.
The DE must remain completely dry to function as an abrasive and absorbent agent. Moisture, such as rain or heavy dew, causes the fine powder to clump and become inert, rendering it useless as an insecticide. Apply the powder in the mid-morning after dew has evaporated, or on a windless day when rain is not forecasted for the next 24 to 48 hours.
A hand duster or bellows is the preferred tool for application, as it creates a fine, light coating that settles evenly. Applying too thick a layer is a common mistake, as grasshoppers will avoid walking through a visible, heavy pile of powder. Aim for a thin, nearly invisible film on the soil surface, the lower parts of plant stems, and areas where grasshoppers congregate.
Targeting the surfaces grasshoppers frequent is more effective than coating entire plants. Focus application on ground surfaces, pathways, and the base of plants where grasshoppers rest or move between feeding spots. Reapplication is necessary after any significant rainfall or heavy overhead watering, as moisture neutralizes the powder’s drying action.
Safety Profile and Impact on Beneficial Insects
When using diatomaceous earth for pest control, only Food-Grade Diatomaceous Earth should be used in home gardens and around people and pets. Filter-grade or pool-grade DE has been heat-treated, changing its silica structure into a crystalline form that is hazardous if inhaled.
Food-grade DE is low in toxicity to humans and animals, but the primary safety concern relates to inhalation of the fine dust. The powder can irritate the lungs, eyes, and nasal passages, so wearing a dust mask and gloves during application is recommended. Once the dust settles, the risk drops significantly, and the product poses no chemical risk if ingested.
The mechanical action of diatomaceous earth means it does not discriminate between pest and beneficial insects. Any insect that crawls through the powder, including beneficial species like ground beetles, ladybugs, and bees, will be affected by abrasion and desiccation.
To minimize the impact on pollinators, apply the product late in the evening after bees and other daytime foragers have returned to their hives. Avoiding the direct dusting of flowers and open blossoms protects flying pollinators. Focusing the application on the base of plants and the surrounding soil targets crawling pests like grasshoppers while reducing the risk to beneficial insects.