Don't be blinded by the striking colors of a leaf hopper. They may remind you of cute insects, but there is nothing pleasant about their presence. They are a nuisance in agriculture and horticulture. These insects can feed on many garden plants and even spread diseases to your crops.
Leafhoppers are so copiously prevalent and damaging, yet gardeners ignore them. Ignoring their presence can be costly if you are growing vegetables and beans in your garden for consumption. It is crucial to act fast if you notice these pests in your garden. Here are some measures of how to get rid of leafhoppers and ways you can identify them.
What Are Leafhoppers
Leafhoppers are insects belonging to the Cicadellidae family, which contains over 20,000 species. Some are green and brown, and some are yellow, often with colorful markings, depending on the species. The adults are the size of a grain of rice with piercing-sucking mouthparts and truncated wings. Nymphs do not have wings and are generally lighter in color than adults. Both nymphs and adults spring forward or backward when disturbed and may even walk sideways like crabs.
All leafhopper species feed on plant sap, but the plant choice varies depending on the type. They feed on plants by sucking sap from leaves, with some species simultaneously injecting toxins that cause plant diseases. If juicy leaf options are unavailable, they may migrate to agricultural regions to feast upon vegetables, herbs, and flowers.
The most commonly occurring leafhopper varieties in your garden comprise the turfgrass leafhopper, the two-spotted leafhopper, and the potato leafhopper. Many confuse them with the planthopper. Leafhoppers and planthoppers look similar and do the same sort of damage, but the two are entirely different insects. Planthoppers belong to the Delphacidae family with a more angular, wedge-like body.
Life Cycle
Leafhoppers go through three life stages: egg, nymph, and adult. In one growing season, leafhoppers may produce two or three generations in your garden. Therefore, the entire life cycle can be present in your garden.
In late spring, females lay about six eggs daily on the underside of leaves and plant barks. The eggs are white and oval. They hatch in 6 to 9 days into tiny nymphs that molt 5 times, growing larger each time before becoming flying adults. The entire cycle takes about three weeks.
Where Do Leafhoppers Live
Leafhoppers are highly adaptable insects that can survive anywhere on the continent supporting vascular plant life. This includes tropical rainforests, deserts, mountains, coastal areas, grasslands, and wetlands. The most populated ones are in or around agricultural regions with abundant food and favorable climate.
Leafhoppers are also very commonly found in a suburban environment with gardens, especially ones that feed on ornamentals like the rose leafhopper. They feed on above-ground plant stems or leaves.
Signs of Leafhopper Infestation
Besides spotting the leafhoppers, the damage they leave behind indicates an infestation. Here are some signs:
Leaf Damage
Leafhoppers usually feed on the upper and lower surfaces of terminal leaves at the end of branches, removing chlorophyll and causing tiny white spots called stippling. These spots can eventually merge into larger blotches, leaving the affected leaves with a bleached, speckled appearance. Over time, this extensive damage weakens the leaves, causing them to yellow, curl, or dry out.
Hopperburn
Hopperburn usually affects potatoes, beans, alfalfa, and other legumes and is caused by the potato leafhopper. These insects inject toxic saliva into the plant while feeding on its sap, leading to visible symptoms like yellow or brown leaf edges.
Over time, these affected areas can curl, dry out, or die completely, making the leaves look burned. Plants suffering from hopper burn may also show signs of dwarfing, stress, and, in severe cases, a complete failure to thrive.
If leafhoppers suck the sap from plants, they will drain the nutrients and moisture required for plant health, disrupting physiology. Plants may grow weak and lose vigor. Moreover, the wounds from the feeding allow fungi or bacteria to enter, resulting in secondary infections, further affecting the growth and health of the plant.
Premature Death
Leafhoppers bite into leaf tissues and suck their sap, which injures plant cells and leaves. This injury reduces the plant's efficiency in photosynthesis, weakening its general health. Where total leaf destruction is extensive and continuous, the plant will not survive long under its growth and development, resulting in premature death.
Bacterial Diseases
Some diseased leafhopper species can pass their disease to the host plant while feeding. While sucking on plant juice, they inject saliva with disease pathogens such as viruses and phytoplasma into the plant.
For example, the beet leafhopper transfers the bacterium that causes citrus stubborn disease and the beet curly top virus in vital crops like beans, cantaloupe, cucumber, spinach, squash, watermelon, and many more.
Honeydew
After feeding on stem fluids, the leafhoppers deposit honeydew, a sticky, sugar-rich substance, on the surface of leaves and other plant parts. Plant surfaces coated in honeydew appear glossier and sticky to the touch.
Over time, a black soot-like fungus, called sooty mold, grows on these surfaces. It seems like a dark gray, powdery coating. It prevents the plants from photosynthesizing, which affects growth and crop yields.
If there are leafhoppers on your plants, you will also notice white, papery lifecasts underneath the leaf surfaces. As part of their growth cycle, the leafhopper nymphs shed their exoskeletons during molting. The cast skins are typically light in color and delicate in texture. The presence of these cast skins is a signal that the leafhoppers are feeding and growing in the area.
Eggs
Leafhoppers lay their eggs in protected locations on plants, often inside the leaf sheaths or midribs. These areas provide a safe, sheltered environment from harsh environmental conditions and predators so that the eggs can develop. The eggs are typically white or pale yellow and clustered together. As the eggs mature, they may change color or become more noticeable.
How to Get Rid of Leafhoppers
Leafhoppers can cause extensive damage in great numbers. It is better to take action before they can harm your plants.
1. Cut Off Dead and Infested Branches
Pruning branches infested with leafhoppers can prevent further infestation. The adults, nymphs, and eggs may be feeding somewhere in the foliage, which means removing them will eliminate the entire life cycle. Focus on cutting off branches with damage, especially those at the center of the infestation, to reduce the pest population significantly.
Late fall through winter is ideal for pruning because it prevents the leafhoppers and their young from overwintering bags. After cutting, burn the debris or secure it in a trash bag and place it far away from your garden. The leafhoppers can escape and reinfest another tree or shrub.
2. Release Parasitic Wasps
Destroying leafhoppers and controlling other pests while at it could be as simple as releasing parasitic wasps in your garden. When released to an infested site, the female wasps deposit their eggs in the leafhopper’s eggs. The wasp larvae develop by feeding on the unborn nymphs. This feeding habit affects the life cycle of the leafhoppers, wiping out an entire generation.
You need to attract the adults into your garden, where they will lay eggs to increase the wasp larva population. The larva will then decrease the leafhopper population. Adult wasps are attracted to areas with plentiful food sources such as carrot flowers, asters, brassicas, verbenas, and legumes.
3. Introduce Neem Oil
Neem oil, like horticultural oil, contains oil-based components and other insecticidal properties that suffocate various insects. However, it is only effective on the eggs of the leafhoppers, a stage that lasts up to 10 days. You could drop handpicked leafhoppers in a bucket of diluted neem oil water to die, but they are not easy to catch. The next best thing to do would be to spray the affected trees with the neem oil-water mixture that is harmless to plants.
Ensure you are using pesticide neem oil or purely diluted neem oil. They are harmless to humans and other animals unless accidentally ingested. They will likely affect the digestive system. Therefore, remember to wear all your protective gear before spraying your plants.
4. Spray Chemical Pesticide
A mild leafhopper infestation does not affect your garden much, but a severe one is deadly. It can wreak havoc, and the only solution may be to kill these pests with chemicals. It is suitable for a severe infestation and may be more practical than other methods.
For maximum effectiveness, you should focus on the timing of application instead of trying to find the best insecticides. The insecticide should be applied when the nymphs and eggs are still developing because adults can escape. Ensure you follow all label directions and check before use that the insecticide is appropriate for the treated plant. Some insecticides are harmful to certain plants.
5. Diatomaceous Earth
If you do not want to rely on chemicals out of fear that they may harm beneficial insects, you can choose organic pesticides like diatomaceous earth (DE). DE is one of the most recommended natural remedies for any pests, including leafhoppers, as it is less damaging to pollinators.
Diatomaceous earth is the fossilized, abrasive remains of prehistoric oceanic life. After mixing ¼ cup of DE with 1 gallon of water, the solution can be sprayed on dry leaves for even application. Apply it only when the forecast calls for dry weather as rain washes it away, which requires reapplication.
6. Bacillus Thuringiensis
Another approach is Bacillus thuringiensis (Bt), a naturally occurring bacterium common in some soils that targets pests. It contains an active ingredient, a crystal protein that paralyzes insects’ digestive systems. The infected insect stops feeding and dies from starvation or a ruptured stomach.
For optimum results, spray the BT on affected plant leaves and avoid irrigating for two days after treatment. When applying BT, ensure you have the right strain for the pest you want to control and that you are coating the eggs which should also be in the larval stage. Lastly, remember to follow the label directions.
7. Nematodes
Releasing beneficial nematodes in moist spring soil that feed on leafhoppers' eggs is another natural biological control option. They’re especially effective when applied during the season after leafhoppers reproduce. For maximum effectiveness, the nematodes must be watered in moist soil immediately after purchase. A suitable season for application is between April and September when soil temperature is around 12-20ºC.
Nematodes should be used following the suppliers’ instructions immediately after purchase. You should water the soil before and after application to ensure it is sufficiently moist for nematode activity and survival. Repeat applications may be necessary.
8. Water in the Morning
Morning watering reduces damage from leafhoppers. If you water early, you have an entire day for the moisture to dry out, lowering the risk of moisture-related fungal diseases when plants are wet overnight. Plants lose their natural defenses against fungal diseases, making them defenseless against pests like leafhoppers.
Besides, early watering gives the plants a good chance to replenish moisture so they can absorb it before the day’s heat causes evaporation, leaving them refreshed and healthy. And healthy, well-watered plants are more resistant to pest damage since they can heal from minor feeding injuries more effectively.
9. Companion Planting
An essential tool in organic gardening is companion planting. Growing the right vulnerable crops near certain plants with natural pest control abilities reduces the leafhopper population and keeps your garden pest-free. For example, the white apple leafhopper primarily feeds on apples. They do not attack the fruit but feast on the mature leaves instead.
The apple trees can be accompanied by flowering herbs such as dill, parsley, or cilantro. The strong aroma of these leafy herbs will drive leafhoppers away as well as lure predatory wasps that feed on them to dwindle their numbers. This approach protects your crops and supports the health of your soil and surrounding plants.
10. Release Predatory Insects
Some beneficial predatory insects that prey on leafhoppers and their young include ladybugs, lacewings, and minute pirate bugs. When these insects are released in the garden, they help kill off leafhoppers in all life cycle stages, along with other pests like aphids, beetles, and mites, which are equally damaging as leafhoppers.
To ensure predatory insects remain in your garden, you should create a conducive living environment for them. Plant various flowers in your garden to provide plenty of food sources. Include water sources so they can stay hydrated and avoid using chemicals that could harm them.
11. Floating Row Covers
Installing floating row covers at the start of the growing season may be the easiest way to shield the plants from leafhoppers and other pests. Covering plants with lightweight, breathable fabrics creates a protective barrier, preventing the pests from reaching the foliage without depriving the plant of its sunlight, air, and water needs.
Setting up row covers early traps leafhoppers from gaining access to your plants and prevents damage. However, it is essential to remove the covers periodically to allow the bees to access the flowers for pollination if you are growing crops that rely on pollinating insects like bees. Ignoring this step may affect fruit production.
