Insects are part of a healthy garden ecosystem. Bees and other pollinators ensure a plentiful harvest from herb and veggie gardens and fruit trees, while ladybugs and praying mantises help control plant-damaging pests. When fruit worms, aphids, Japanese beetles, roaches, and their destructive ilk gain a toehold in a garden, they can quickly ruin your crops. A targeted insecticide can help prevent this.
The best insecticides for pest control in vegetable gardens are fast and effective at killing destructive bugs without harming their beneficial brethren—or pets and humans. They’re even better when they’re easy to apply without specialized equipment. Read on to learn how the best insecticides for vegetable gardens work and why the following options rank as some of the best in their respective categories.
- BEST OVERALL: Monterey LG6135 Garden Insect Spray
- BEST BOTANICAL: Neem Bliss Organic 100% Cold Pressed Neem Seed Oil
- BEST INSECTICIDAL SOAP: Natria 706230A Insecticidal Soap
- BEST LONG-LASTING: BioAdvanced Bayer Advanced Insect Spray
- BEST FOR CATERPILLARS: Bonide (BND803) Leaf Eating Worm & Moth Killer
- BEST FOR JAPANESE BEETLES: ST GABRIEL ORGANICS Milky Spore Grub Pest Controller
- ALSO CONSIDER: Bonide (BND857) Pyrethrin Garden Insect Spray
Types of Plant Diseases
When fruit trees and vegetables are looking poorly, it’s important to understand the reason before reaching for any pest treatment, since most insecticides have no effect on diseases. The presence of insects feeding on the plant is the most obvious indicator that an insecticide will help. Below are more ways to figure out the cause.
Fungal, Bacterial, and Viral
Plant diseases, caused by fungus, bacteria, or virus, can cause symptoms that look similar to insect damage, like holes in leaves, leaf discoloration or malformation, and stunted growth. Diseases often appear first as discolored spots on leaves. Some affect stems or fruits exclusively, while root diseases weaken the plant, leading to stunting or wilting of the above-ground parts.
In fungal diseases, spots are often round and may appear as brown concentric circles, while bacterial and viral diseases often look more angular, as they follow the leaf veins. As disease spreads, leaves may take on a powdery or fuzzy appearance before turning brown or black and finally dropping. Choose an appropriate fungicide to treat fungal diseases. Plants suffering from viral or bacterial disease must be severely pruned or removed altogether.
Beetles and caterpillars chew irregular patterns, often consuming leaves beginning at the tender edges and working their way in. Some insects eat the softer parts of leaves and avoid the tougher veins, giving leaves a lacy appearance.
If you need to kill insects, it’s best to choose a product formulated to control that particular pest. Broad-spectrum insecticides kill a diverse variety of bugs, both “good” and “bad.” Care must be taken to minimize collateral damage to non-target species.
What to Consider When Choosing the Best Insecticide for Vegetable Gardens
In selecting the best insecticide for vegetable garden use, it’s important to match your expectations with the abilities of the product. Some features to consider are organic versus chemical formulas, targeted pests, duration of efficacy, and liquid versus granular products.
Organic vs. Chemical
The active ingredients in organic insecticides are derived from natural sources, such as minerals, plants, and bacteria. Although many of these products can harm both beneficial bugs and pests, they have a short residual activity time after application, which helps reduce collateral damage.
Timing of the application is critical to ensure effective control, as these products are most effective on immature insects. Organic insecticides can be comparatively expensive, with a less immediate effect and a potential need to reapply multiple times for complete control.
Chemical insecticides typically work much faster, last longer, and cost less per application than their organic counterparts. As with organic insecticides, chemical insecticides can kill both good and bad bugs, so care must be taken to avoid collateral damage.
These products are derived from chemicals that also can be toxic to people, pets, and the environment if used or stored improperly. The slow rate at which they break down in the environment can lead to buildup in soil or groundwater if chemical insecticides are overused.
While broad-spectrum insecticides can kill hundreds of different insect species, most vegetable crops are only threatened by one or two different pests. To minimize the chance of damaging beneficial insects, gardeners should try to identify and target the specific enemy. Evidence of tomato fruit worms, for instance, appears as an entry hole in the tomato.
Mexican bean beetles resemble pale orange ladybugs, but they chew on bean plant leaves. Squash bugs attack the stems of squash plants, right at ground level; the larvae bore into the stems, weakening and eventually killing the whole plant. Although the same broad-spectrum insecticide may be appropriate for all three pests, application timing and location on the plant will be different for each.
Another way to target pests that eliminates collateral damage is by using insecticides that only kill the targeted bugs. Bacillus thuringiensis (Bt), for instance, is a biological control for caterpillars that is safe for other insects. Milky spore kills Japanese beetle grubs in the ground, but it’s safe for earthworms and all other soil dwellers.
Liquid insecticides, either targeted or broad spectrum, are fast acting because they immediately deliver the active ingredient to the problem. Spray liquid insecticides directly on foliage, stems, or the root zone of plants to eliminate active pests. Liquids come in both concentrated and ready-to-spray formulas. Concentrates, which cost less per treatment, must be diluted with water before use. Pricier ready-to-spray products save time and the mess of mixing.
Most granular insecticides are broad-spectrum treatments that are effective and persistent at treating soil-level garden pests—but will harm beneficial bugs, too. Granules are easy to apply—simply sprinkle on the soil in the problem area—and store in a closed canister.
Most insecticidal garden dusts are broad-spectrum treatments. They store easily, have a long shelf life, and work fast when applied to foliage, stems, or soil, as needed. Dusts can be tricky to apply evenly, however, especially on lower leaf surfaces. These chemicals are easily and efficiently applied with a garden duster that mixes the product in a gentle air stream and dispenses the dust in a cloud to evenly coat the plant.
Gardeners should always heed manufacturer safety precautions when applying insecticides. Safety measures may include wearing protective gear like long sleeves, rubber gloves, safety glasses, and a respirator mask. Be aware of the risks and possible reactions for exposure to the product. Keep product labels intact, and never reuse insecticide containers for other purposes.
Be prepared for emergencies. Call 911 immediately if someone shows signs of an adverse reaction to insecticide exposure—which can include stinging eyes, rashes, blisters, dizziness, nausea, or diarrhea. Then check the product label for directions on first aid for exposure to that product. Call the Poison Control Center at (800) 222-1222 for first aid information.
For the safety of plants, pay close attention to sunlight and temperature, as some insecticides for vegetable gardens may damage foliage if applied in the heat or bright sunlight. Protect pollinators and other beneficial insects by avoiding treatments while plants are in bloom.
When insects are present at all life stages, part or all of the mature population may be controlled by insecticide on contact. But often, in early stages, the egg protects the developing insect, so in a few weeks the pest problem resurges. The more advanced the infestation, the more important it is to apply an insecticide that lasts long enough to kill on contact and be effective on eggs. Otherwise, with less persistent insecticides, frequent applications will be needed to banish bugs.
Our Top Picks
There are many options when it comes to insecticides for a vegetable garden. Listed below are some of the best in specific categories. These garden insecticides are made by the most trusted brands in the industry to effectively control difficult pests, yet are safe for people and pets when used as directed.
Monterey Garden Insect Spray rapidly controls many insects including caterpillars, leafminers, codling moth, tent caterpillars, thrips, borers, and fire ants. Use it on vegetable plants, lawns, and outdoor ornamentals. The active ingredient, spinosad, is a bacterial product produced by fermentation. Spinosad affects the nervous system of insects that consume it, killing them within 1 to 2 days.
It’s odorless, approved for organic gardening, safe around people and pets, and can be used up to the day of harvest. It comes as a liquid concentrate. To use, mix with water according to label directions and apply with a trigger, handheld, backpack, or hose-end sprayer.
If bugs aren’t the only thing threatening your plants, Neem Bliss neem oil can help. It quickly kills aphids, whiteflies, and other soft-bodied insects, as well as spider mites, plus it’s equally effective against fungal diseases like powdery mildew, black spot, and rust. Use it on veggies, shrubs, trees, fruits, and even houseplants. It’s also a good dormant season spray for fruit trees, killing insects and eggs that may be overwintering in the bark.
Neem oil is a naturally occurring pesticide, extracted from seeds of the neem tree. Used as a pesticide for centuries (and having numerous other household and industrial purposes), it reduces insect feeding, acts as a repellent, and makes it harder for insects to grow to maturity and lay eggs. Mix the concentrate according to label directions and apply with a sprayer, but don’t use it on foliage during hot weather to avoid foliage burn.
Natria Insecticidal Soap is a multipurpose insecticide that kills on contact and works in minutes. It is safe to use indoors or out for treatment of whiteflies, aphids, mealybugs, mites, and many other listed insects. Use it against the adult, larval, or nymphal stages of pests.
This is not a preventative treatment; targeted pests must be present for the treatment to work. It is safe to use up to the day of harvest on fruits and veggies as well as on roses, flowers, and houseplants. The convenient ready-to-use trigger spray bottle makes it easy to apply. Be sure to target upper and lower leaf surfaces as well as stems.
BioAdvanced Vegetable and Garden Insect Spray is a powerful, long-lasting topical spray that lasts up to 3 months. Use it to save fruit and vegetable crops from more than 100 insect pests, including Japanese beetles, aphids, and tomato hornworms. Follow the label directions carefully to protect beneficial insects like bees. Once it dries, the garden area is safe for people and animals.
The active ingredient, cyfluthrin, is a stomach poison that kills feeding insects within 24 hours. Pest insects must consume treated plant tissue for the chemical to work properly, so reapplication may be necessary as plants grow. The 32-ounce concentrate makes up to 64 gallons of spray and treats up to 5,333 square feet.
Bonide Thuricide is a biological control for the larval stages of moths and butterflies. It has no effect on adults of the species and is completely safe around people, pets, other insects, and animals—including birds that may eat treated caterpillars. Use it wherever caterpillars are damaging a garden, such as on tomatoes, greens, cabbages, and even roses.
Bt (Bacillus thuringiensis kurstaki) is a bacterial insecticide toxic to caterpillars when eaten; it dissolves and colonizes in the gut, killing off the caterpillars in 1 to 2 days. Mix the concentrate with water according to directions. Apply to foliage using a hose-end or pressurized tank sprayer.
St Gabriel Organics Milky Spore is a formulation of the Paenibacillus popilliae bacteria, which occurs naturally in soil. It causes a disease within the white Japanese beetle larvae as they develop underground, but it has no effect on other soil dwellers like desirable earthworms.
Use where Japanese beetles have been problematic to significantly reduce local populations of this noxious exotic species. The larvae consume milky spores as part of their natural feeding pattern. As the bacteria colonize, larvae die within 1 to 3 weeks, releasing millions of new bacteria spores into the surrounding soil.
Spread milky spore granules with a calibrated garden spreader at any time spring through fall. Though the product begins to work immediately after application, full control—which protects against the beetle for up to 20 years—takes 1 to 3 years in warm climates, and up to 5 years in cool areas. A 20-pound bag treats up to 7,000 square feet.
Fast and effective Bonide Pyrethrin Garden Insect Spray controls aphids, beetles, webworms, leafhoppers, and many other yard and garden insects on vegetables, trees, flowers, and ornamental plants. Pyrethrin, one of the active ingredients, naturally occurs in chrysanthemums and is considered one of the best biodegradable insecticides.
It kills by targeting insects’ nervous systems and quickly degrades, leaving no objectionable residue. Bonide Pyrethrin Garden Spray is safe to use on vegetables up to the day of harvest. Mix the concentrate with water and apply with a sprinkler can, hand sprayer, or low-pressure sprayer.
FAQs About Insecticides
Now that you know more about vegetable garden insecticides, there may be new questions about how to use them. Before you enter a battle with bugs, check out the following answers to common questions about the best insecticides for vegetable gardens.
Q. How do I keep bugs out of my vegetable garden?
Insects tend to attack unhealthy plants. To keep pests away from your veggies, start by providing plentiful sunlight, fertile soil, and good air circulation, along with consistent water that plants need to thrive. Allow beneficial species like praying mantises, garden spiders, and ladybugs to stay in the garden and feast on pests. When necessary, apply an insecticide that will quickly and efficiently eliminate insect pests.
Q. What can I spray on my vegetable garden to kill bugs?
The possibilities are numerous. Do your best to identify the culprit before choosing and applying garden insecticides. Bonide (BND857) Pyrethrin Garden Insect Spray is the best overall product because it kills a wide variety of insect pests, is easy to apply, and limits damage to non-targeted insects when applied as directed.
Q. What pesticides are safe for vegetable gardens?
There are numerous organic and nonorganic pesticides that are safe for vegetable gardens when applied according to label directions. Pay special attention to the recommended timing of the application for each crop to avoid damaging plants or non-target insects.
Q. What is the safest pesticide for vegetables?
An argument could be made for Neem Bliss Organic 100% Cold Pressed Neem Seed Oil as one of the safest pesticides for vegetable gardens. It is plant based and nontoxic to people. Still, be cautious to protect non-targeted species like bees and other beneficial bugs. Follow the label directions carefully, and avoid spraying flowering plants, especially during times of high pollinator activity.
Giving your garden the best growing conditions will go a long way toward pest prevention. In order to grow strong and healthy, plants need adequate sunlight, water, air circulation, and fertility. Healthy plants are resilient to minor insect infestations. However, sometimes outside influences lead to big bug problems, and gardeners may need a little help.
When garden ecology gets out of balance, it may be necessary to spray. Sometimes the best choice is a natural or organic product. In other situations, synthetic insecticides are more effective. Choose a bug killer that will quickly and decisively eliminate pests, while minimizing damage to beneficial insects, people, and animals.