Leafhoppers are small insects belonging to the family Cicadellidae. These insects are typically slender and wedge-shaped, usually measuring between 2 to 30 millimeters in length, though many common pest species are about 1/8 to 1/4 inch long. They inhabit nearly every environment that supports vascular plant life, including deserts, grasslands, wetlands, and forests, where they are commonly found on the stems and leaves of plants.
Direct Interaction with Humans
Leafhoppers are not harmful to humans and do not bite or sting. Accidental probing of human skin is medically harmless and does not transmit disease. Their piercing-sucking mouthparts are adapted to extract sap from plants, not to bite humans.
When a leafhopper might accidentally probe human skin, it typically causes only temporary, minor discomfort. It poses no health risk, as leafhoppers do not transmit human diseases. Their primary interest lies in consuming plant sap, making their interaction with people incidental and of little concern.
Effects on Plants
Leafhoppers primarily impact plants through their feeding habits, which can cause noticeable damage. They use their specialized mouthparts to extract sap from plant cells, leading to symptoms such as tiny white spots, stippling, on leaves. Prolonged or heavy feeding can result in leaves curling, yellowing, or becoming stunted. Some species inject a toxin while feeding, causing a condition called “hopperburn,” where leaf tips and margins curl, turn yellow to brown, and become brittle, appearing scorched.
Beyond direct feeding damage, certain leafhopper species can transmit plant pathogens, including viruses, phytoplasmas, and bacteria. Examples include the aster leafhopper, which spreads aster yellows disease, causing yellowing, dwarfing, and distorted foliage in various vegetables and ornamentals. The beet leafhopper can transmit curly top virus, affecting crops like beans, beets, and tomatoes, leading to crinkled and dwarfed leaves. Another example is the glassy-winged sharpshooter, which vectors the bacterium Xylella fastidiosa, responsible for diseases like Pierce’s disease in grapes. These pathogens are plant-specific and do not pose a threat to human health.
Managing Their Presence
Managing leafhopper populations focuses on protecting plants. Integrated Pest Management (IPM) strategies offer a balanced approach to control. Encouraging natural predators, such as ladybugs, lacewings, spiders, minute pirate bugs, and parasitic wasps, can help reduce leafhopper numbers, as these beneficial insects feed on leafhopper eggs and nymphs. Avoiding broad-spectrum insecticides helps preserve these natural enemies.
Physical control methods are effective. Using strong water sprays can dislodge leafhoppers from plants, while row covers or netting can serve as physical barriers to prevent them from accessing vulnerable plants. Applying kaolin clay to plant surfaces can deter feeding and egg-laying. Additionally, insecticidal soaps and neem oil can be used to manage populations. Removing weeds and plant debris from garden areas can also minimize overwintering sites and host plants for leafhoppers.