How to Get Rid of Bugs on Outdoor Plants

Bugs and pests can be a major nuisance in an outdoor garden or on houseplants kept outdoors. Not only are they unsightly, but they can do serious damage by eating away at leaves, flowers, roots, and stems. Getting rid of bugs requires persistence and patience, but with the right techniques, you can protect your plants. Here are some of the most effective methods for getting rid of bugs on outdoor plants.

Identify the Pests

The first step is identifying what bugs are infesting your plants. Different pests call for different control methods. Here are some of the most common plant bugs:

Aphids

These soft-bodied insects come in many colors like green, black, grey, or white. They cluster on stems and undersides of leaves, sucking sap. Heavy aphid infestations can cause curled, yellowing leaves and stunted plant growth.

Spider Mites

Too small to be seen with the naked eye, these pests look like moving dots on leaves. Leaves become stippled and yellowed. Fine webbing may cover infested plants.

Mealybugs

Recognizable by their distinct white fuzzy or waxy coating, mealybugs cling to stems and leaves. They cause yellowing, wilting, leaf drop, and stunted growth.

Thrips

Slender pests that rasp plant tissue and drink expelled plant juices. This causes silvered, dried out patches on leaves and petals.

Japanese Beetles

Metallic green and copper beetles that eat holes in leaves, flowers, and ripe fruit. They skeletonize leaves between veins.

Scale Insects

Immobile pests adhered to stems and leaves. Heavy infestations coat plant parts with wax, sap, and shed skins, damaging growth.

Take a close look at any infested plants and compare to pictures to positively identify the bug culprits. This ensures you use treatments that specifically target the pests at hand.

Remove Infested Plant Parts

Eliminate bugs already on plants by pruning away heavily infested parts. Using clean, sharp pruners or garden scissors, cut off:

• Stems, leaves, flowers, and fruits covered with pests
• Areas with eggs or egg sacs
• Branches and stems with scale infestations

Discard all infested trimmings in sealed bags in household trash, not the compost pile.

For houseplants, isolate infested plants away from uninfested ones so pests do not spread.

Pruning away infested parts removes populations of plant pests and gives you a head start on control. Follow up with other treatments to fully eradicate bugs.

Apply Insecticidal Soap

Insecticidal soaps containing potassium salts of fatty acids are effective at controlling soft-bodied insects like aphids, thrips, whiteflies, and spider mites. The soap solutions penetrate the insect cuticle and cause cell disruption, leading to dehydration and death.

Mix according to label directions and spray directly on bugs and undersides of leaves. Coat all plant surfaces, especially where you see pest activity. Reapply every 5-7 days for 2-3 weeks until pests are gone.

Insecticidal soap works by contact only and has no residual effects. It is safe for people, pets, beneficial insects, and the environment when used as directed.

Use Horticultural Oils

Like insecticidal soaps, horticultural oils smother and kill soft-bodied insects and mites through contact. The oils coat the pests and clog breathing pores, leading to suffocation. The oils also disrupt feeding, mating, egg laying, and mobility.

For outdoor plants, use lightweight summer oils which evaporate rapidly. Mix according to label instructions and coat all leaf surfaces, stems, branches. Reapply every 7-14 days for several applications.

Horticultural oils are safe for many plants. But test spray on a small area first, as some plants are sensitive. Avoid spraying during hot, humid conditions. Oils are toxic to fish and aquatic invertebrates, so prevent runoff.

Apply Neem Oil

Extracted from the seeds of the neem tree, neem oil kills insects via multiple modes – as a contact poison, anti-feedant, and insect growth regulator. It contains azadirachtin which interferes with insects’ hormones systems. This disrupts molting, metamorphosis, reproduction, feeding behavior and suppresses populations.

Mix neem oil according to label directions and thoroughly coat all plant parts, especially the undersides of leaves. Reapply every 7-14 days for a few weeks until insect infestations are under control.

Neem oil is low toxicity to people and pets when used as directed. It also has minimal effects on beneficial insects like ladybugs, butterflies and bees. Avoid spraying neem during hot, sunny conditions which can burn plant tissues.

Apply Insecticide Dusts

Insecticide dusts like diatomaceous earth (DE) are very effective against crawling insects and soil-dwelling pests. The dusts have microscopic sharp edges that cut through insect bodies, causing dehydration and death. Dusts also abrade and destroy the waxy cuticles of soft-bodied insects.

For outdoor use, apply a thin coat of DE dust to soil, leaf undersides, and crevices of stems and branches. Reapply after rain or watering. DE is safe for pets, people and the environment.

As an organic alternative, also try dusting with talcum powder, clay, ashes, or lime. These dessicate and irritate insects. Avoid breathing in dusts during application.

Apply Systemic Insecticides

Systemic insecticides are absorbed by plants and make the vascular tissues and plant sap toxic to feeding insects. As pests feed, they ingest the insecticide and die. Systemics provide residual control for 1-2 weeks or more.

Some common systemic insecticides for outdoor plants include:

• Imidacloprid – Apply as a soil drench or tree injection. Kills aphids, thrips, whiteflies, beetles, and other sap feeders.
• Acephate – Spray on leaves and stems to control chewing pests like caterpillars and beetles.
• Dinotefuran – Apply as foliar spray, soil drench or granules. Controls aphids, whiteflies, leafhoppers, leafminers.

Systemic insecticides require accurate dosing. Carefully follow label application rates and re-treatment intervals. Only use on recommended plant species. Improper use can damage plants.

Use Beneficial Nematodes

Beneficial nematodes are microscopic roundworms that parasitize and kill over 200 species of soil-dwelling insects, including grubs, root maggots, cutworms and other beetle larvae. The nematodes sense carbon dioxide emitted by pests, then enter and release toxic bacteria. This stops feeding within 24-48 hours.

For outdoor use, mix nematodes with water and apply using a watering can, hose sprayer or irrigation system. Seek out products suited for outdoor/landscape use. Make sure soil is moist before and after application. Reapply every 2-4 weeks as needed. Beneficial nematodes only control soil-dwelling pests.

Set Out Traps

Traps are useful for monitoring pest populations and reducing numbers of flying and crawling insects. Different trap types include:

• Sticky traps – Coated with adhesive to snare crawling bugs and flying insects like fungus gnats, thrips, leafminers. Use yellow or blue colors which attract pests.
• Pheromone traps – Lure in certain insect species using sex pheromones. Trap Japanese beetles, codling moths, armyworm moths, and other targets.
• Pitfall traps – Sink cans or cups flush with soil to catch crawling insects like sowbugs, beetle grubs and larvae. Fill 1/3 with soapy water.

Place appropriate trap types near infested plants, replacing as they fill up. Trapping helps suppress pest numbers, but usually must be combined with other control methods.

Use Physical Barriers

Row covers, fabric screens, and clear plastic domes can exclude pests and protect plants. Drape fabrics directly over plants, or construct cages or cloches supported by hoops. Secure edges with stones, boards or landscape pins. Remove covers periodically to allow for pollination and airflow.

These barriers keep pests from reaching plants. But they must be installed before insects are present. Monitor enclosed plants regularly for any pests that become trapped under covers.

Encourage Natural Predators

Ladybugs, lacewings, hoverflies, predatory mites, tachinid flies, praying mantises, birds, frogs, lizards and other beneficial predators feed on plant pests. Provide habitat to attract these allies to your garden:

• Plant nectar sources like dill, fennel, cosmos, sunflowers, and daisies.
• Provide water sources like birdbaths, small ponds, or moist soil.
• Put up nest boxes suitable for birds and bats that eat insects.
• Allow vegetation like long grasses, brush piles, or mulch to shelter insect predators.
• Avoid broad-spectrum insecticides that kill beneficials. Use target-specific organics instead.
• Consider purchasing and releasing predators like ladybugs, lacewings, or predatory mites.

Use Companion Plantings

Certain plants naturally repel or confuse pests, protecting nearby “companion” plants. Interplant these throughout the garden:

• Marigolds repel aphids, nematodes, and other garden pests.
• Garlic, chives, onions, leeks emit sulfur compounds that deter aphids, beetles, and caterpillars.
• Mint deters aphids, flea beetles, spider mites, cabbage worms, and squash bugs.
• Catnip, rue, and tansy repel a wide variety of common insect pests.
• Nasturtiums lure aphids away from vegetables and ornamentals.
• Petunias help protect plants from a range of sucking and chewing insects.

Practice Crop Rotation

Rotating plant families in growing areas from season to season reduces pest pressure. Many insects and diseases overwinter in soil and readily re-infest the same crops.

Move plants from these families to separate sections of garden each year:

• Solanaceae (tomatoes, potatoes, peppers, eggplants)
• Cucurbitaceae (cucumbers, melons, squash)
• Brassicaceae (cabbage, broccoli, kale, Brussels sprouts)
• Alliums (onions, leeks, garlic, shallots)
• Legumes (beans, peas, lentils)

At least 3-4 year rotations are needed to disrupt pest life cycles. Keep detailed garden maps to remind you of rotations.

Keep Plants Healthy

Healthy, vigorous plants better withstand and outgrow insect damage. Give plants a strong start with:

• Rich organic matter worked into soil
• Optimal spacing for air circulation
• Regular watering and fertilization
• Proper sunlight
• Pruning and thinning of overcrowded growth

Monitor regularly for early signs of stress, disease, nutrient deficiencies. Address issues promptly to keep plants robust. Remove and destroy severely damaged plants which can harbor heavier pest infestations.

Time Plantings Carefully

By planting at recommended times, plants mature when conditions favor growth over pest activity:

• Plant cool season crops (spinach, lettuce, cabbage) early spring and fall to avoid summer insects.
• Delay sowing warmth-loving plants (tomatoes, squash, corn) until soil has warmed fully to avoid cold-season pests.
• Get fall cole crops established well before pests overwinter or migrate south.

Check seed packets and regional planting guides for ideal planting times. Schedule plantings carefully to avoid peak activity periods of key pests.

Clean Up Thoroughly

Many insects and diseases overwinter in plant debris. Do a thorough garden cleanup to remove these pest habitat sources:

• Clear all fallen leaves, stems and pulled weeds. Compost only pest-free debris.
• Till or hoe soil to disrupt pest eggs and expose larvae to predators.
• Rake up all dropped fruit and vegetables – do not compost.
• Remove weeds, which provide cover and alternate food sources for pests.
• Disinfect reusable growing containers before storage.

Field cleanup removes many overwintering pests so they cannot threaten next year’s crops.

When to Call a Professional

For moderate insect infestations, diligent monitoring and prompt treatment using these organic methods allows you to effectively protect outdoor plants. But seek professional help for:

• Unidentified pests causing extensive damage. An expert can advise best control options.
• Persistent large-scale infestations not resolved by organic measures. Professionals have access to stronger synthetic pesticides if needed.
• Presence of invasive pests new to your region. Early control helps avoid wider establishment. Monitoring by experts helps detect new invaders.
• Tree/wood-boring insects. Specialized injectable treatments may be needed to kill borers under bark.

With some knowledge of pest biology and persistence using multiple organic approaches, you can eliminate most bug problems and keep your outdoor plants thriving pest-free. Reach out to landscaping professionals for any severe or unresolved issues requiring more potent control measures.

Frequently Asked Questions

What are some signs my outdoor plants have insect pests?

Look for:

• White specks that fly up or crawl around when foliage is disturbed – likely young nymphs/larvae.
• Clusters of small insects on the undersides of leaves or stems.
• Tiny yellow, black, or red dots that look like moving sand – mites, thrips, aphids.
• White cottony tufts on stems and leaves – likely mealybugs.
• Leaves stippled with yellow dots or streaks.
• Leaves with dried, brown edges or skeletonized tissue between veins.
• Tunnels bored into trunks/stems and sawdust-like frass – signs of boring insects.
• Distorted, curled or dropped leaves and flowers.
• Presence of honeydew, black sooty mold, or tiny webs.

What safety measures should be taken when applying insecticides?

• Read and follow all label safety directions.
• Avoid inhaling sprays – wear a respirator if needed.
• Wear gloves, long sleeves, pants, and goggles to avoid skin and eye exposure.
• Wash thoroughly with soap after use.
• Avoid spraying on windy days.
• Keep children and pets away from treated areas until dry.
• Apply targeted sprays carefully, avoiding blooms to protect pollinators.

How can I avoid bringing pests indoors on outdoor plants?

• Inspect plants closely for pests before bringing indoors. Treat if needed.
• Isolate outdoor plants from indoor collections for 1-2 weeks, watching for signs of pests.
• Hose off outdoor plants with a strong spray of water to dislodge larvae, eggs and adults.
• Prune away any infested plant parts or consider repotting in sterile media.
• Apply prophylactic insecticidal soap or neem oil before bringing inside.

Are insecticidal soaps safe for plants and people?

Yes, insecticidal soaps are non-toxic to mammals and birds because they target only insects through specific modes of action. Some plants like ferns, bleeding hearts, and tender seedlings can be sensitive to soaps. Test spray on a small area first. Avoid direct inhalation and follow label safety directions.

Conclusion

Battling bugs on outdoor plants takes some work, but is well worth the effort to protect your landscape and garden plants. Identify the pests accurately so you can select appropriate organic control methods to target the specific insects involved. Employ multiple tactics like pruning, trapping, barriers, beneficial insects, and least-toxic sprays. With persistence using an integrated pest management approach, you can eliminate destructive bugs while keeping your plants – and the environment – healthy.