Dealing with pesky bugs eating outdoor plants can be extremely frustrating for any gardener. However, there are numerous effective and organic methods to deter bugs without resorting to harmful chemical pesticides. This comprehensive guide will provide insight into the most common plant-eating bugs, why they are attracted to certain plants, and actionable tips to prevent them from feasting on your outdoor vegetation.
Identifying Common Plant-Eating Bugs
The first step is identifying what types of insects or bugs may be munching on your foliage. Here are some of the most prevalent critters and pests:
Aphids
These tiny, soft-bodied insects come in a variety of colors like green, black, red, or white. They tend to cluster on stems, leaves, and anywhere they can sink their piercing-sucking mouthparts into plants to extract sap. High populations can cause leaves to curl, wilt, or become deformed.
Japanese Beetles
These metallic green and bronze beetles devour leaves between the veins, leaving behind a lacy skeleton. They target roses and over 300 other plant species.
Caterpillars
The larvae of moths and butterflies chew on leaves and bore into stems or fruits. Common culprits are tomato hornworms, cabbage loopers, and gypsy moth caterpillars.
Slugs & Snails
These slimy mollusks use rasping tongues to make holes in leaves, flowers, and stems. They leave behind telltale silvery trails.
Earwigs
Earwigs are nocturnal insects with signature pincers on their abdomen. They nibble tiny holes in leaves and petals or chew through stems at soil level.
Ants
Some ant species protect and farm aphids or scale insects to feed on the honeydew secretions from these sap-sucking bugs. They can also chew on plants directly.
Whiteflies
These tiny white winged insects cluster on the undersides of leaves and use their piercing mouthparts to suck sap. They cause yellow stippling or leaf curling.
Spider Mites
Too small to see with the naked eye, these mites form webs on leaves and puncture plant cells to feed on the juices inside. Leaves turn stippled, bronze, or yellow.
Flea Beetles
These tiny jumping beetles feed on seedlings and vegetation. They chew tiny holes or pits in leaves, stunting growth.
Cutworms
The fat, soft-bodied larvae of moths chew through stems at soil level, causing seedling collapse. They also munch leaves and buds.
Why Bugs Are Attracted to Certain Plants
There are a few key reasons why specific bugs tend to target certain plants:
- Food source – Bugs need plant sap, nectar, pollen, or other tissues to survive. Some have specialized mouthparts to tap specific plants.
- Life cycle host – Many bugs require certain plant species to complete their life cycles. For example, monarch caterpillars only feed on milkweed.
- Habitat – Plants provide food, shelter, water, and egg-laying sites. Bugs are drawn to the microclimate around preferred plant structures.
- Scents – Plant chemicals or fragrances can lure pollinators but also make vegetation more vulnerable to pests.
- Lack of diversity – Monocultures offer an unlimited buffet for adapted insects. Diverse gardens limit spread of any single species.
- Stress – Struggling plants send out chemical distress signals. Bugs hone in on weakened, diseased, or drought-stressed plants.
- Few natural predators – Without birds or beneficial insects, pests can explode into populations unchecked.
Organic Ways to Stop Bugs Eating Plants
The good news is there are many organic and non-toxic methods to prevent or manage plant-munching bugs without resorting to harmful pesticides:
Remove Infestations Manually
For mild infestations, manually removing the bugs can be effective for preventing larger outbreaks. Here are some techniques:
- Hand pick pests off plants and drop them in soapy water. Target large, slow pests like caterpillars, snails, slugs, or beetles.
- Prune out heavily infested leaves, stems, or branches. Dispose of them in sealed bags.
- Use pressurized water to dislodge aphids, mites, whiteflies, or other small insects. Avoid excessive high pressure sprays that can damage plants.
- Apply sticky barriers like Tanglefoot, Stickem, or insect glue around trunks to trap crawling bugs.
Cultivate Healthy Soil
Healthy loamy soil with lots of organic matter provides habitat for beneficial microbes and predatory insects that keep pest levels in check naturally.
Fertilize Moderately
Over-fertilization causes excessive growth that makes plants vulnerable to infestations. Moderate fertilizer levels avoid this issue.
Clean Up Debris
Fallen leaves, branches, and garden debris provide shelter for overwintering pests and eggs. Keep the garden tidy.
Use Row Covers
Floating spun polyester row covers create a physical barrier against flying and crawling insects while still allowing air, light, and water through. Drape over plants or secure with hoops for protection.
Try Companion Planting
Certain plants naturally repel or confuse pests, protecting their neighbors through chemical excretions. For example, marigolds deter aphids, basil repels mosquitoes and flies, onions ward off cabbage moths, etc.
Rotate Crops
Don’t plant the same vegetable or flower species in the same spot year after year. This prevents buildup of adapted pests.
Use Organic Sprays
Botanical oils, neem oil, insecticidal soaps, kaolin clay, and spinosad products smother or poison bugs while safe for people, pets, and the environment. Reapply after rain.
Attract Natural Predators
Lady bugs, green lacewings, birds, bats, and other predators feast on plant pests. Provide habitat like native flowers, bird houses, and sources of water. Avoid pesticides that would harm them.
Install Physical Barriers
Floating row covers (as mentioned earlier) or protective netting create a physical barrier against most pests while allowing airflow, light, and irrigation.
Apply Diatomaceous Earth
This powder made of crushed fossils cuts into soft-bodied insects like slugs, causing dehydration and death. Apply around stems and leaves. Reapply after rain. Safe for pets when dry.
Set Out Traps
Pheromone traps lure in target pests with sex attractants or food baits. Sticky traps catch wandering bugs. These can both monitor and reduce populations.
Leverage Beneficial Nematodes
These microscopic worms prey on soil-dwelling pests like grubs, weevils, root maggots, and cutworms. Water them into the soil.
Use a Strong Water Stream
For mild infestations, simply spraying plants regularly with a strong stream of water can physically knock off and kill small crawling insects like aphids, spider mites, or earwigs. Avoid damage with too high pressure.
Apply Horticultural Oils
Lightweight refined petroleum oils smother soft-bodied insects like aphids, mealybugs, thrips, and scale on contact. Coat leaves evenly and underneath for full coverage.
Hand Pick Nighttime Pests
Some bugs only feed at night like earwigs, armyworms, slugs, and snails. Search plants after dark with a flashlight and remove any pests found.
Set up Beer Traps
Shallow dishes of beer attract and drown slugs and snails prowling for plants at night. Bury the dishes in soil flush with the ground.
Sprinkle Diatomaceous Earth
This powder made of crushed sea fossils cuts into soft-bodied slugs and snails. It’s safe for pets when dry. Reapply after rain. Avoid breathing in the dust.
Block Ant Access
Seal ant entry points into potted plants with sticky barriers like Tanglefoot. Use borax bait traps near ant nests to kill the colony.
Hang Yellow Sticky Traps
Small flying insects are attracted to the color yellow. Traps draw in whiteflies, aphids, fungus gnats, leafminer moths, and more.
Use a Bug Vacuum
A handheld battery vacuum with a narrow hose is an easy way to suck up Japanese beetles, aphids, whiteflies, and other small plant pests without damaging delicate foliage and flowers.
Apply Kaolin Clay
This white mineral powder coats plants and makes them unrecognizable to pests. It deters many insects and prevents sunburn while being safe for people, pets, and beneficials.
Remove Alternate Weed Hosts
Many weeds serve as secondary food sources for pests like thrips, aphids, Japanese beetles, and cucumber beetles. Keep the area around your plants weed-free.
Use Floating Row Covers
Lightweight spun polyester fabric draped over plants creates a physical barrier against most flying and crawling pests while still allowing air, light, and water through.
Introduce Predatory Insects
Release live ladybugs, lacewings, minute pirate bugs, parasitic wasps, or predator mites from commercial suppliers. They will prey on target pests and establish colonies.
Practice Crop Rotation
Rotating plant families in a certain area from year to year disrupts pest life cycles so they cannot thrive. For example, avoid following tomato plants with more tomatoes or eggplant.
Remove Infested Material
Prune off pest-infested leaves, stems, flowers, or fruits. Dispose of this material immediately in sealed bags to prevent spread. Compost only after hot composting first.
Apply Horticultural Oils
These oils smother soft-bodied insects like whiteflies, mealybugs, aphids, thrips, and scales through suffocation on contact. Coat leaves for full coverage including undersides.
Install Tree Bands
Wrap barrier bands covered with sticky adhesive around tree trunks to trap crawling pests like beetles, caterpillars, ants, earwigs, and gypsy moth larvae trying to scale trees.
Maintain Proper Sanitation
Remove fallen leaves, debris, and garden refuse regularly to eliminate pest shelter and egg-laying sites. Destroy infected material immediately.
Use Organic Insecticidal Soap
Potassium salts of fatty acids destroy soft-bodied insect membranes but are non-toxic to people, pets, beneficials, birds, and the environment. Spray plants evenly.
Apply Neem Oil
This oil from the neem tree coats plants with an insecticide and repellent while also fostering growth. Spray leaves including undersides for full coverage against chewing and sucking insects.
Plant Nectar Plants
Flowering plants provide food for predatory and parasitic insects like hover flies, minute pirate bugs, parasitic wasps, tachinid flies, lady beetles, lacewings, etc.
Rotate Mowing Heights
Alternate mowing lawn areas low and high to disrupt shelter and life cycles of surface pests like chinch bugs, sod webworms, and cutworms.
Hang Blue Sticky Traps
Thrips are attracted to the color blue. Traps draw them in and cling to their wings and bodies. Monitor to detect infestations early.
Use Beneficial Nematodes
These microscopic worms prey on soil-dwelling pests like grubs, root weevils, maggots, and armyworms. Water them into soil for biological control without chemicals.
Apply Spinach Oil Extract
This non-toxic oil extract made from spinach plant fatty acids repels thrips, whiteflies, spider mites, leafminers, caterpillars, beetles, and other plant pests when sprayed on.
Use Synthetic Pyrethroids
Pyrethrins derived from chrysanthemum flowers are formulated into synthetic insecticide sprays or concentrates for severe infestations of chewing and sucking insects, being sure to carefully follow all label safety guidelines.
Install Screening or Netting
Aluminum, nylon, or steel screening can exclude larger biting and chewing pest insects when used to cover planting beds, creating a protective barrier while maintaining air flow and light.
Frequently Asked Questions About Stopping Plant Pests Naturally
What bugs are eating holes in my plant leaves?
Chewed holes with ragged edges are typically caused by caterpillars, slugs, snails, earwigs, beetles, leafminers, or grasshoppers. Other signs like leaf notching, skeletonized foliage, or tiny pits indicate more specific pests. Proper identification is key for control.
How do I get rid of aphids on plants naturally?
Blast plants with water, apply horticultural oils or neem oil, or introduce ladybugs and lacewings. Soap spray or neem oil also work. Trim off heavily infested parts, avoid overfertilizing, and coat susceptible plants with kaolin clay.
What bug spray is safe for vegetable plants?
Some safer sprays for edible plants include insecticidal soaps, neem oil, spinosad, Bacillus thuringiensis (Bt), pyrethrin, or essential oils like clove, peppermint, or rosemary oils. Always follow label directions. Light horticultural oils only on certain plants.
How do I stop bugs from eating my cauliflower?
Cover young cauliflower heads by tying outer leaves above them. Use floating row covers secured over plants. Apply parasitic wasps or neem oil for root maggots. DE will deter slugs. Rotate sites each season to disrupt pest lifecycles in the soil.
What can I spray on plants to keep bugs off?
There are several organic sprays to deter bugs including neem oil, insecticidal soap, horticultural oils, kaolin clay, garlic oil, hot pepper wax, and spinosad products. Test small areas first and coat leaf undersides for full protection. Reapply frequently.
What are the small white bugs on my plants?
If they fly up when disturbed, they are likely whiteflies. Check leaf undersides where whiteflies cluster. Other possibilities include mealybugs, aphids, or scale. Identifying the specific pest will determine the best organic control methods. Look closely with a magnifying glass.
What insecticide kills aphids but not bees?
Some aphid insecticides considered relatively bee-safe include neem oil, pyrethrins, azadirachtin, insecticidal soap, Beauveria bassiana fungal spray, and certain essential oils like thyme oil. Always follow label precautions and directions. Avoid spraying blooms directly.
What bugs does Sevin insecticide kill?
Carbaryl is the active ingredient. It controls over 100 insects including Japanese beetles, aphids, emerald ash borer, leafhoppers, mole crickets, bluegrass billbug, caterpillars, mosquitoes, squash bugs, spittlebugs, clover mites, and more beetles, bugs, worms, moths, etc. Do not use around edible plants.
What bug killer is safe for pets?
Some pet-friendly options include diatomaceous earth, neem oil, insecticidal soap, citrus oil spray, kaolin clay spray, or a mild 1% bleach solution to deter ants. Read labels to ensure safety around children and pets before using any pest control products.
Conclusion
By identifying the most common plant-eating pests, understanding why certain bugs target specific plants, and leveraging multiple organic control methods, you can keep your outdoor vegetation lush and pest-free without relying on toxic chemical solutions. Consistent monitoring along with prevention strategies like row covers, removing infestations manually, applying organic sprays, and attracting beneficial predators can successfully deter a wide array of stubborn garden bugs while keeping your plants, pets, pollinators, and the planet protected. With dedication and patience, your efforts at natural pest control will eventually pay off in vibrant, healthy outdoor plants. For any severe or ongoing infestations, consult a professional entomologist for targeted advice and control solutions tailored to your specific insect pests and affected plants.