Leafhoppers can be a serious issue thanks to their ability to weaken plants by feeding and spreading diseases. If you see them hopping about your garden plants, it’s time to take action! Here’s how to identify, prevent, and get rid of leafhoppers.
Tiny bugs that hop into the air, fleeing your approach. Grasshopper, you think. But these are way too small and hard to see if they don’t move. Your beans look like they have a nitrogen deficiency, growing stunted and yellowing at the outer edge of the leaves. Apple leaves look speckled. Perhaps your carrot tops are yellowing and twisting.
Leafhoppers are like vampires on your plants. They pierce the cells and suck out the fluids, and like vampires, can leave your plants weakened or even spread other diseases. Their damage results in millions of dollars of crop losses every year.
What Are Leafhoppers?
Leafhopper is the common name for a wide variety of similar insects from the family Cicadellidae, in the order Hemiptera, also known as “true bugs.”
Leafhoppers are tiny bugs, often only a quarter of an inch long, with piercing-sucking mouthparts. They puncture plant tissues and drink the fluids inside. This unique mouthpart is called a proboscis. Unlike other insects with proboscises (proboscides is also correct), true bugs cannot roll theirs up. It remains rigid.
Leafhoppers can cause direct injury to plants through their physical feeding and by toxins injected into the plant with their saliva. They also carry plant diseases.
Small and slender, leafhoppers vary in color from dull or pale to bright, glossy, and even striped. As their name suggests, their rear legs are specialized for jumping, which they often will do when you approach.
Leafhoppers go through incomplete metamorphosis, meaning they come out of the egg already looking somewhat like the adult. Depending on the species, they go through several nymphal stages and molt several times as they grow before developing wings as an adult.
With so many species of leafhopper, many plants can become a target. Ornamentals, grapes, garden crops, roses, and field crops like soybeans and alfalfa can be attacked by leafhoppers.
Common Leafhopper Species
Potato leafhopper, Empoasca fabae, affects more than just potatoes. It can be a common pest of beans, apples, dahlias, peas, eggplants, strawberries.
Small, only an ⅛ of an inch long, and wedge-shaped, they are lime-green and have six white spots behind their large eyes. The nymphs are wingless, pale green or yellow, and almost translucent. If your garden is adjacent to an alfalfa field, you may see a sudden influx of these bugs after the hay is cut.
Aster leafhopper, Macrosteles quadrillineatus, is a dull light-green and also has six white spots on its head. The wings are a smokey gray. M. quadrillineatus is a vector for the disease known as “aster yellows.” Plants commonly infected include carrots, lettuces, celery, and flowers in the aster family. New foliage appears yellowed and twisted.
Beet leafhopper, Circulifer tenellus, is a serious pest. Feeding does minor damage to the plant, but the bug is a vector for Beet Curly Top virus. As it sounds, beets and other plants like tomatoes that are infected show curled up, small leaves, sometimes with swollen veins.
The Candy-striped leafhopper, Graphocephala coccinea, is a brightly colored bug with a fun name. They are teal colored with brilliant red-orange stripes and yellow legs. Common in North America, it won’t seem as fun if it attacks your blackberries, roses, or rhododendrons. G. coccinea is a vector for Pierce’s disease, which affects common yard trees and ornamentals.
So many species of bug belong to the leafhoppers group that narrowing down a few symptoms can be tricky. Finding the adult or nymph stages is an obvious sign. Leafhopper damage, regardless of species, often looks similar due to their feeding method.
Look for these signs of leafhoppers:
V-shaped yellowing of leaves that may look like a nutrient deficiency. This characteristic is known as “hopper burn.”
Yellowed areas may turn brown after continued feeding
Adults hopping away when you approach
Tips and buds curled over and wilting
Nymphs present on the undersides of leaves
Control and Prevention
Prevention and Cultural Practices
Unless you live in southern areas like Texas, Oklahoma, and states along the Gulf of Mexico, your leafhopper problem likely originates from bugs flying north in summer. As they spread on the wind, they can end up anywhere.
Potato leafhoppers, for example, are carried by spring weather systems. The adult bugs fly up into storm clouds and are carried along, dropped into new fields by downdrafts several days and hundreds of miles later.
Monitoring for leafhopper arrival in your area can be done with garden inspections or yellow sticky cards. Check the undersides of leaves for eggs and nymphs. Adults may be seen fleeing at your approach. They can jump a couple of feet.
Their arrival timeframe depends on your location. Some states with significant problems offer tracking websites to view their migration progress.
Row covers can prevent new adults from landing on your plants and laying eggs. Go for spun-bonded or plastic materials. You’ll have to remove them when the plants flower to allow pollinator access.
Encourage Natural Enemies
Leafhoppers have many natural predators. The same lady beetles, lacewings, spiders, and parasitic wasps that feed on aphids, thrips, scale insects, and other garden pests will also make lunch of leafhopper eggs and larvae.
Encourage them to set up shop by maintaining pollinator plantings–many also eat nectar. Avoid broad-spectrum insecticides. Mulch and coarse debris give them a place to hide from their enemies.
Keeping your garden and property inviting and safe for these beneficial insects can go a long way toward minimizing leafhopper damage. A healthy population of predatory insects can make leafhoppers just a nuisance instead of a big problem.
Treatments for Leafhoppers
In most areas of the country, leafhoppers do not overwinter but fly north, hitching a ride on the winds in spring. For this reason, crop rotation, while helpful for other pests, does not have much effect on leafhopper numbers the following year.
If you detect leafhopper nymphs early in the season, you can treat the undersides of leaves with neem oil, horticultural oil, or insecticidal soap. But be cautious. A few nymphs and light damage are preferable to harming your pollinators and beneficial insects.
Planting Resistant Cultivars
While no plants are resistant to leafhopper damage, some are resistant to the diseases they carry. It is often the disease, not the insect feeding, which causes the most problems.