Leafhoppers are small, common insects found globally, known for their distinctive ability to jump. These herbivores, belonging to the family Cicadellidae, primarily consume plant sap from a wide array of vegetation. This article explores their characteristics, developmental stages, feeding habits, and impact on plant health.
Identifying Leafhoppers
Leafhoppers are generally small, typically ranging from 1/8 to 1/4 inch (3-6 mm) in length, though some species, like the glassy-winged sharpshooter, can reach about 1/2 inch (12 mm) long. Their bodies are often wedge-shaped or elongated, holding their two pairs of wings in a roof-like manner over their backs when at rest. Many species exhibit drab camouflage colors like brown, gray, green, or yellow, while some are brightly colored or have intricate patterns, helping them blend into host plants.
A distinguishing feature is the presence of one or more rows of small spines along their hind legs. These legs are adapted for jumping, allowing them to rapidly jump or fly away when disturbed. They possess large, often prominent eyes. Nymphs, the immature stage, resemble smaller versions of adults but lack fully developed wings and may vary in coloration.
Life Cycle and Development
Leafhoppers undergo incomplete metamorphosis, a developmental process with three primary stages: egg, nymph, and adult. Adult females typically insert eggs into tender plant tissue, which can create tiny, pimple-like wounds. These eggs often overwinter within the plant, hatching in late winter or early spring.
Upon hatching, wingless nymphs emerge, appearing as smaller, less developed versions of the adults. Nymphs grow by molting, shedding their exoskeleton multiple times, usually five times, as they progress through increasingly larger stages called instars. These shed skins, often pale and papery, can sometimes be found on the underside of leaves. After their final molt, they reach the adult stage, becoming capable of reproduction and flight. Most leafhopper species produce multiple generations within a single growing season.
Feeding Habits and Preferred Environments
Leafhoppers are plant sap-feeders, utilizing specialized piercing-sucking mouthparts to extract fluids from plant vascular tissues. They feed on a diverse range of host plants, including grasses, shrubs, trees, garden plants, and agricultural crops. While some species are generalists, feeding on many plant types, others are highly host-specific, such as the rose or grape leafhopper.
These insects can be found in nearly any habitat supporting vascular plant life, including forests, grasslands, wetlands, and deserts. They commonly inhabit areas with abundant host plants, such as gardens, agricultural fields, and natural ecosystems. Leafhoppers often prefer to feed on the underside of leaves, which provides them with protection and access to the plant’s sap.
Effects on Plants
Leafhopper feeding can cause noticeable damage to plants. Their sap-sucking activity removes chlorophyll, leading to small, pale or bleached spots on leaves, a symptom known as stippling. In severe infestations, continuous feeding can cause leaves to curl, yellow, turn brown, and even wilt or die. This direct feeding can reduce plant vigor and stunt growth. Some species also inject toxins during feeding, resulting in symptoms like “hopperburn,” where leaf tips and margins turn yellow to brown, become brittle, and appear scorched.
Beyond direct feeding damage, leafhoppers are vectors of various plant diseases. As they move from plant to plant, their piercing-sucking mouthparts can transmit viruses, bacteria, and phytoplasmas from infected to healthy vegetation. Examples of diseases spread by leafhoppers include aster yellows, which causes yellowing, dwarfing, and distorted foliage in carrots, celery, and other plants. The beet leafhopper (Circulifer tenellus) transmits the curly top virus, affecting crops like sugar beets, tomatoes, and melons, leading to crinkled, dwarfed leaves and reduced yields. The glassy-winged sharpshooter (Homalodisca vitripennis) vectors Xylella fastidiosa, a bacterium responsible for diseases like Pierce’s disease in grapes.