Leafhoppers are tiny, green, wedge-shaped insects that can cause serious damage to plants in gardens and farms. Getting rid of leafhoppers requires diligence and multiple control methods, but it can be done organically without pesticides. This comprehensive guide will provide in-depth information on identifying leafhoppers, understanding their lifecycle, preventing infestations, and controlling populations with mechanical, physical, biological and chemical treatment options.
What Are Leafhoppers?
Leafhoppers are tiny sap-sucking insects belonging to the Cicadellidae family, part of the Hemiptera order of true bugs. There are over 20,000 known leafhopper species found all over the world. In North America, the most common pest species are the potato leafhopper and the variegated leafhopper.
Leafhoppers have characteristic wedge-shaped bodies that allow them to fit between tight places and veins on leaf surfaces. They have wings that are held tent-like over their bodies at rest. Leafhoppers range in size from just 3-4 mm long. Their bodies are often colorful, marked with spots, lines or patterns in white, yellow, green, brown and black.
These bugs are weak jumpers and fliers, moving from plant to plant in search of sap. Both nymphs and adults have piercing-sucking mouthparts they use to feed on plant fluids. Large infestations can kill leaves, stunt growth and cause leaf curling, yellowing, browning and dropping. Leafhoppers spread phytoplasmas that cause plant diseases. They also excrete honeydew while feeding that encourages mold growth.
Lifecycle of Leafhoppers
Leafhoppers have simple, incomplete metamorphosis with egg, nymph and adult stages:
- Eggs – Females lay eggs inside plant tissue using a saw-like ovipositor. Eggs are typically laid on the undersides of leaves. Each female can lay 20-100 eggs or more. The eggs are bean-shaped and very small, less than 1 mm long.
- Nymphs – Nymphs hatch from eggs in 4-20 days depending on species and temperature. Nymphs (also called instars) resemble small wingless adults. There are 5 nymphal instars which each molt 3-10 days after hatching before reaching the next stage.
- Adults – The 5th instar molts into the adult winged form in 10-20 days after the last molt. Adults live 2-6 weeks. The females start laying eggs about a week after reaching maturity.
Leafhopper generations overlap continuously through the growing season. In warmer climates, leafhoppers may produce 6 or more generations per year. The adults can overwinter in plant debris or bark crevices.
Identifying Leafhoppers
It is important to properly identify leafhoppers before attempting to control them. Here are some tips for recognizing leafhoppers:
- Check the shape – Leafhopper bodies are wedge-shaped and somewhat flattened, allowing them to fit in tight spaces on plants.
- Look for jumping or flying – Disturbing the plant may cause leafhoppers to jump or take short flights. This movement distinguishes them from other true bugs.
- Note the wings – Adult leafhoppers have two pairs of wings that are held roof-like over their bodies when at rest. Nymphs are wingless.
- Check for white markings – Many species have distinctive white, yellow or colored markings on their heads and bodies.
- Note the feeding damage – Look for white stippling, yellowing, curling, wilting, or leaf drop. Honeydew and sooty mold may be present.
- Look on the undersides – Leafhoppers often feed and lay eggs on the undersides of leaves. Check leaf undersides for the insects themselves, their shed skins and eggs.
Leafhoppers can be hard to tell apart from planthoppers and treehoppers, which are related but different families of insects. A hand lens or macro lens can help discern key traits like the number of spines on the legs. For severe infestations, specimens can be identified by agricultural extension offices.
Preventing Leafhopper Infestations
Preventing leafhopper damage is preferable to dealing with a full-blown infestation. Here are some tips to avoid problems with leafhoppers:
Remove Weeds
Leafhoppers thrive on weeds like yellow nutsedge and curly dock. Eliminate weeds around gardens and crop fields to remove leafhopper breeding grounds. Mow down taller weeds regularly.
Use Row Covers
Floating row covers can exclude leafhoppers from crops when installed soon after planting. Use the finer 0.9-1.0 oz/sq yd covers with full sides buried for best results.
Use Aluminum Mulch
Research shows aluminum reflective mulch can disrupt leafhopper landing and reproduction, reducing infestations in some crops.
Plant Resistant Varieties
Some crop varieties have genetic resistance to diseases spread by leafhopper feeding. Choose resistant varieties of grapes, potatoes, beans, lettuce and other susceptible plants.
Use Healthy Transplants
Inspect transplants closely and reject any with signs of leafhopper damage. Starting with clean plants prevents bringing leafhoppers into your garden.
Control Ants on Plants
Leafhoppers feed on honeydew produced by ants that tend aphids or other sap-sucking insects on plants. Controlling ants can in turn reduce leafhopper problems.
Avoid Over-fertilizing
Leafhoppers prefer the rapid, tender growth caused by excessive nitrogen fertilization. Use the minimum fertilizer needed for good growth.
Clean Up Debris
Leafhoppers overwinter in plant litter. Fall cleanup of leaves, weeds and crop residues can reduce next year’s populations.
How to Get Rid of Leafhoppers Using Mechanical Controls
Mechanical control methods physically remove or kill leafhoppers using simple tools, traps and hands-on techniques. Here are some effective options:
Hand-picking
Pluck visible leafhoppers from leaves and discard them in soapy water. Hand-picking works best for light infestations on small plants. Wear gloves – leafhoppers can bite!
Sticky Traps
Yellow and blue sticky cards can catch adult leafhoppers when placed near infested plants. Sticky traps alone rarely control populations, but help monitor when combined with other methods.
Leaf Blowers & Vacuums
Using handheld blowers directed at the undersides of leaves can help dislodge and vacuum up leafhoppers. Repeat often to catch newly hatched generations.
Bug Zappers
Blacklight zappers do attract and electrocute some adult leafhoppers, but are very limited in effectiveness for population control.
Row Covers
Installing floating row covers can physically exclude leafhoppers. Use fine mesh covers sealed at the edges to prevent access.
Squishing
Simply squashing leafhoppers with fingers when found can eliminate a few. Try not to squish them on the plant itself to avoid spreading diseases.
Traps
Homemade traps like yellow bowls filled with soapy water can catch some leafhoppers, but must be cleared and reset daily. Traps supplement other control methods.
Physical & Biological Controls for Leafhoppers
There are several physical and biological control methods that can be applied to deter or kill leafhoppers without using any chemicals:
Water Sprays
Strong sprays of water can knock leafhoppers off plants to reduce feeding and egg laying. Avoid damaging delicate plants and repeat often.
Reflective Mulches
Silver reflective mulch and aluminized fabric mulches can interfere with leafhopper landing and reproduction. Research shows they deter some species like potato leafhopper.
Resistant Varieties
Grow leafhopper-resistant crop varieties like Andes lettuce, Romaine lettuce, Defender grape, and Columbia potato to avoid damage. Certain varieties have physical or chemical traits that deter pests.
Natural Enemies
Ladybugs, lacewings, minute pirate bugs, and other beneficial predators feed on leafhopper eggs and nymphs. Avoid pesticides that kill these allies. Plant flowers for them.
Entomopathogenic Fungi
Fungal pesticides contain Beauveria bassiana spores that infect and kill leafhoppers. Apply these organic products preventatively or when nymphs are active.
Entomopathogenic Nematodes
Nematodes like Steinernema attack and kill leafhopper nymphs in the soil. Use nematodes derived from host insects, not plant pests. Apply them to soil according to label.
Repellent Plants
Interplanting garlic, chives, petunias, marigolds and other plants shown to repel leafhoppers may deter them from adjacent plants. Results vary depending on species.
Mass Trapping
Large numbers of baited sticky traps can reduce leafhopper populations without insecticides. Work best in greenhouses and high tunnels when combined with biocontrols.
Vacuuming Adults
Portable vacuums can suck up leafhopper adults but must be emptied frequently to prevent their escape. Most effective for light infestations only.
Chemical Treatments for Leafhoppers
If non-chemical solutions fail to reduce leafhopper damage to acceptable levels in the garden or field, chemical insecticides may be warranted. Here are some of the safest chemical options:
Insecticidal Soaps
Soap-based insecticidal sprays kill leafhoppers on contact through membrane disruption and dehydration. Treat leaf undersides to reach insects. May require several applications.
Neem Oil
Neem oils and products like Azadirachtin disrupt leafhopper growth, feeding behavior, and reproduction. Neem must coat insects to be effective. Repeat applications are needed.
Pyrethrins & Pyrethroids
Pyrethrum and plant-based pyrethrins kill leafhoppers on contact. Synthetic pyrethroids like permethrin provide residual activity for longer control. Avoid overusing pyrethroids.
Diatomaceous Earth
Diatomaceous earth (DE) abrasively damages the waxy covering and causes desiccation in leafhoppers. Dust DE onto dry foliage, especially leaf undersides where leafhoppers hide.
Horticultural Oils
Refined petroleum spray oils smother insects on treated surfaces. Apply dormant or summer oils to control leafhopper nymphs, eggs and overwintering adults.
Kaolin Clay
Kaolin particle films deter feeding and egg-laying by leafhoppers. It must coat insects to be effective. Avoid using when temperatures exceed 90°F.
Microbial Insecticides
Bacillus thuringiensis (Bt) products specifically target leafhopper nymphs and other immature true bugs, but have little effect on adults. It must be ingested to work.
Frequently Asked Questions About Controlling Leafhoppers
What kills leafhopper eggs?
Insecticidal soap, neem oil, and horticultural oils applied to leaf undersides where eggs are laid can smother and kill leafhopper eggs if spray coverage is thorough. Systemic insecticides do not kill the eggs.
How do you get rid of leafhoppers naturally?
Natural ways to control leafhoppers include handpicking, water sprays, sticky traps, reflective mulches, resistant plant varieties, beneficial insects, repellent plants, and biopesticides. Avoid over-fertilizing and maintain plant health.
What chemical kills leafhoppers?
Chemical insecticides that kill leafhoppers include pyrethrins, pyrethroids like permethrin, neonicotinoids such as imidacloprid, sulfoxaflor, insecticidal soaps, neem oil, diatomaceous earth, kaolin clay, horticultural oils, and microbial Bt targeting nymphs.
What insecticide will kill leafhoppers?
Insecticidal soap, neem oil, pyrethrum, pyrethroids like bifenthrin, permethrin and esfenvalerate, systemic neonicotinoids like imidacloprid, sulfoxaflor, and the microbial Bt insecticide Cry3/Cry23 are registered insecticides that will kill leafhoppers. Avoid overusing any single class of insecticide or the insects may become resistant.
How do you stop leafhoppers from reproducing?
Reducing leafhopper reproduction requires controlling nymphs that become breeding adults. Applying insecticidal soap, neem, or horticultural oils to leaf undersides where nymphs feed and disrupt their development can help break the reproduction cycle. Natural enemies like lady beetles that eat the eggs and nymphs also limit leafhopper reproduction.
Conclusion
Dealing with destructive leafhoppers in gardens and agriculture requires an IPM approach using multiple control strategies. Focus first on cultural practices like removing weeds, using row covers, and planting resistant varieties to prevent infestations from taking hold. For active leafhopper populations, employ mechanical control, natural enemies, physical deterrents, and biological treatments if possible before resorting to insecticides. When chemical intervention is needed to save plants, use more selective and lower-risk products in rotation and avoid over-applying any single pesticide class. Combining multiple organic and least-toxic management options will provide effective, long-term control of troublesome leafhoppers.