The Best Insecticides for Vegetable Gardens

Protect your plants from hungry insects—and yourself from toxic chemicals—with these safe, effective garden bug killers.

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Best Insecticide For Vegetable Gardens

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Insects are part of a healthy garden ecosystem. Bees and other pollinators ensure a plentiful harvest, while ladybugs and praying mantises help control plant-damaging pests—that happen to be other bugs! That’s right, when fruit worms, aphids, Japanese beetles, roaches, and their destructive ilk gain a toehold in a garden, they can quickly ruin your crops. Before that happens, consider using a targeted insecticide.

The best insecticides for 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 understand how the best insecticides for vegetable gardens work and why these six rank so high in their respective categories.

  1. BEST OVERALL: Bonide (BND857) Pyrethrin Garden Insect Spray
  2. RUNNER-UP: Monterey LG6135  Garden Insect Spray
  3. BEST BANG FOR THE BUCK: Garden Safe HG-93179 Neem Oil Extract Concentrate
  4. BEST FOR CATERPILLARS: Monterey LG 6336 Bt Worm and Caterpillar Killer
  5. BEST FOR JAPANESE BEETLES: St Gabriel Organics 80080-P Milky Spore
  6. BEST FOR APHIDS: Safer Brand 5118-6 Insect Killing Soap Concentrate
Best Insecticide For Vegetable Gardens

Photo: depositphotos.com

Before You Buy an Insecticide for Vegetable Gardens

When plants 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. 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.

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. Some diseases affect stems or fruits exclusively. Root diseases weaken the plant, leading to stunting or wilt of the above-ground parts.

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 insects are to blame, 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,” and care must be taken to minimize collateral damage to non-target species. The best insecticides are intended to kill specific insects on specific crops. When gardeners apply them according to label directions and employ the recommended safety precautions, these products pose a very low threat of harm to all except the targeted species.

Features to Look for in Insecticides for Vegetable Gardens

In selecting the best insecticide for your vegetable garden, 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. The 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 can pose health risks 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 a buildup in soil or groundwater if chemical insecticides are overused.

Targeted Pests

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 is safe for earthworms and all other soil dwellers.

Duration

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.

Liquid, Granular, and Dry Dust Application 

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.

Safety

Gardeners should always heed manufacturer safety precautions when applying insecticides. Safety measures may include wearing protective clothing like long sleeves, rubber gloves, safety glasses, and/or a respirator mask. Be aware of the risk 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. The Poison Control Center (800) 222-1222, can also help with 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.

Our Top Picks

These highly rated garden insecticides by the most trusted brands in the industry effectively control difficult pests yet are safe for people and pets when used as directed.

Best Insecticide For Vegetable Gardens Bonide

Photo: amazon.com

1. BEST OVERALL: Bonide (BND857) Pyrethrin Garden Insect Spray

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.

Best Insecticide For Vegetable Gardens Monterey

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2. RUNNER-UP: Monterey LG6135  Garden Insect Spray

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 one to two 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; mix with water according to label directions and apply with a trigger, handheld, backpack, or hose-end sprayer.

Best Insecticide For Vegetable Gardens GardenSafe

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3. BEST BANG FOR THE BUCK: Garden Safe HG-93179 Neem Oil Extract Concentrate

If bugs aren’t the only thing threatening your plants, Garden Safe Neem Oil may come to the rescue—at a great price. 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 house plants. 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 too), 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 on foliage during hot weather to avoid foliage burn.

Best Insecticide For Vegetable Gardens MontereyLG

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4. BEST FOR CATERPILLARS: Monterey LG 6336 Bt Worm and Caterpillar Killer

Monterey Bt Worm and Caterpillar Killer 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 your garden, such as on tomatoes, greens, and cabbages. 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 one to two days. Mix the concentrate with water according to directions. Apply to foliage using a trigger or pressure tank sprayer.

Best Insecticide For Vegetable Gardens StGabriel

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5. BEST FOR JAPANESE BEETLES: St Gabriel Organics 80080-P Milky Spore

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 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 spore as part of their natural feeding pattern and as the bacteria colonizes, larvae die within one to three weeks, releasing millions of new bacteria spores into the surrounding soil.

Spread milky spore granules with a calibrated garden spreader (a 20-pound bag treats up to 7,000 square feet) 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 one to three years in warm climates, and up to five years in cool areas.

Best Insecticide For Vegetable Gardens Safer

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6. BEST FOR APHIDS: Safer Brand 5118-6 Insect Killing Soap Concentrate

Safer Brand Insecticidal Soap uses a formulation of potassium salts of fatty acids to penetrate the cuticles of soft-bodied insects, ultimately causing them to dry out. It’s an inexpensive, easy-to-use, and effective pesticide for a host of common pests including aphids, earwigs, leafhoppers, mealy bugs, mites, sawfly larvae, soft scales, spider mites, and whiteflies.

Insecticidal soap needn’t be consumed to be effective; simply spray on the bugs and they die on contact. It’s safe to use on edibles up until the day of harvest, and will not persist in the environment. Mix according to directions on the label and apply with a trigger or pressure tank sprayer. Avoid spraying insecticidal soap while beneficial insects like bees and other pollinators are present. Highly mobile insects like whiteflies may require multiple treatments for complete control.

FAQs About Your New Insecticide 

Before you enter a battle with bugs, check out these answers to common questions about the best insecticides for vegetable gardens.

Q. What pesticides are safe for vegetable gardens? 

There are numerous organic and non-organic 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. How do I keep bugs out of my vegetable garden? 

Insects tend to attack unhealthy plants, so 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.