Grasshoppers are among the most common herbivorous insects found globally. These creatures belong to the insect order Orthoptera, characterized by powerful hind legs adapted for jumping. They have highly developed chewing mouthparts, making them efficient consumers of vegetation in nearly every terrestrial habitat. Their feeding habits range from casual grazing of wild grasses to the complete devastation of agricultural fields during major outbreaks.
The Grasshopper Diet
Grasshoppers are primarily herbivores, meaning their diet consists overwhelmingly of plant material, including leaves, stems, flowers, and seeds. Most species exhibit polyphagous behavior, classifying them as generalists that feed on a wide variety of available plant species within their environment. This generalist approach allows them to survive even when their most preferred food sources become scarce.
A significant portion of the grasshopper diet centers on grasses, which are monocots, and this preference makes cereal crops such as wheat and corn particularly vulnerable. Other species are considered specialists, restricting their feeding to only a few closely related plant types, often those with fewer defensive compounds. These specialists may also target broadleaf plants, or dicots, including vulnerable garden vegetables like lettuce and beans.
The specific nutritional needs of grasshoppers can influence their plant choices; females often seek out nitrogen-rich plants, such as legumes, for egg production. While their diet is overwhelmingly green, grasshoppers occasionally scavenge on dead insects or decaying organic matter when plant food or moisture is limited.
Identifying Damage Patterns
Grasshoppers possess strong mandibles that shear and chew plant tissues, creating a distinctive pattern of damage that helps identify their presence. The most common sign of their feeding is the appearance of ragged, irregular holes chewed directly into the middle of the leaves. Unlike caterpillars, which often consume plant material starting at the edges, grasshoppers typically create holes throughout the leaf surface as they move.
Defoliation is the most common consequence of their feeding, ranging from minor cosmetic damage to skeletonizing the entire leaf, leaving only the veins intact. The damage pattern differs between life stages; young grasshoppers, known as nymphs, create smaller holes and notches. Adults can consume entire leaves quickly, sometimes eating half their body weight in a single day.
A more serious type of damage involves feeding on the stems and growing tips of plants. When grasshoppers sever tender, newly developing parts or gnaw through the main stem, they can stunt growth or cause the top portion of the plant to fall over. This stem feeding is destructive to young seedlings and vulnerable crops like soybeans and hemp, leading to immediate plant failure.
Protecting Plants from Feeding
Gardeners and farmers can employ several non-chemical strategies to protect vulnerable plants from grasshopper feeding. Physical barriers offer a simple first line of defense, with fine mesh row covers or screened boxes placed directly over plants preventing access. However, the insects can sometimes chew through thinner cloth covers, so strong screening material is a better option.
Introducing or encouraging natural predators is an effective biological control method. This includes:
- Birds, such as chickens and guinea fowl, which prey on grasshoppers at various life stages.
- Beneficial insects like certain wasps and robber flies.
- Applying microbial agents, such as Nosema locustae, a naturally occurring protozoan, to infect and reduce grasshopper numbers over time.
For localized control, some natural dusts and sprays can provide a deterrent or direct contact solution. Diatomaceous earth, a fine powder, works by scratching the insect’s exoskeleton, causing dehydration. Garlic or hot pepper sprays can be applied to foliage to create an unpalatable taste barrier, discouraging consumption.