Using Sevin Dust on Green Beans

Sevin dust is a powerful herbicide that is composed of the chemical carbonyl. It is easy to use and available in granules, as a spray, and of course, as a dust. It works by disrupting the nervous system of insect pests – but unfortunately, it is indiscriminate in that it can negatively impact beneficial pollinators, too.

Sevin dust is safe to use on green beans. It works to get rid of many pests, including aphids, cutworms, moths, grubs, beetles, cutworms, and Japanese beetles. Just make sure you wash and rinse your beans thoroughly before you freeze or eat them, regardless of when you use Sevin dust during the growing process.

As mentioned earlier, Sevin dust is labeled as safe for use on beans. However, there are a few things you will want to be aware of before you decide to use it on your plants. Here’s what you need to know…

What is Sevin Dust?

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Sevin dust is a chemical that can be used in the garden to control a wide variety of pests. It contains the active ingredient carbaryl.

It takes care of insects on contact, affecting them either when they make bodily contact with the chemical or when they ingest it.

It is applied by shaking it via a container throughout the garden, with particular attention paid to the plant parts that the insects are actively feeding upon.

Sevin dust can get rid of the following pests:

• Aphids
• Cutworms
• Japanese beetles
• Squash borers
• Mosquitoes
• Cockroaches
• Beetles
• Moths
• Grubs

It should be applied as soon as you notice an infestation and repeatedly until the infestation is gone. You must apply this chemical when the weather is dry, as rain will reduce the effectiveness of the dust. You can apply it up to seven times per year.

Sevin dust is meant to be applied after you have planted to protect your garden edibles from insect damage. You do have to follow a pre-harvest interval chart, which varies depending on the type of plant you are growing.

While plants like brassicas can be harvested pretty soon after applying Sevin dust, things like apples, tomatoes, peppers, and cherries need a longer interval. Leafy vegetables like kale, collards, lettuce, arugula, spinach, and cabbage also need a longer wait time (referred to as PHI) before they’re safe to eat.

Check the product labels on the specific Sevin products you use to find out when it’s safe to eat the harvest from your vegetable garden.

What are the Risks of Sevin Dust?

Sevin dust is registered with the U.S. Environmental Protection Agency for use on vegetables. However, it is toxic and you do need to be careful when you apply it. The manufacturer suggests waiting three to 14 days before eating beans that were sprayed with Sevin dust, since carbaryl can be moderately toxic.

It can produce adverse effects regardless of whether you inhale it, ingest it, or via skin contact. This is why many countries, like the United Kingdom, no longer allow its sale.

Although you’ll be fine when you use Sevin dust as long as you use it correctly, using too much or harvesting too soon after you have applied it can lead to severe symptoms. You might suffer from black lung disease (especially if inhalation is involved), nausea, lowered blood pressure, blurred vision, diarrhea, breathing difficulties, and more.

Not only that, but pregnant women should avoid using it as it can cause fetal abnormalities.

Despite the risks, it can still be a good solution to get rid of green bean pests, especially when nothing else seems to work. If you must use it, wear personal protective equipment like rubber gloves and a dust mask so you can reduce your contact with the chemicals. Apply only a calm, rain-free day so you don’t have to work in a dust cloud.

Remember that beneficial insects, like bees and butterflies, will also be affected by Sevin dust. It can also affect birds and animals that might feed upon those insects.

Make sure all kids and pets aren’t allowed into the treated area for at least 24 hours. Only apply Sevin dust if you absolutely need to. It is toxic and needs to be treated with extreme caution.

You can remove most traces of this pesticide by thoroughly washing and rinsing your plants. The chemical residues will only exist in very small numbers (parts per million) after that.

Although this technique won’t work as well for plants like peas and green beans, peeling your vegetables can remove almost all lingering residues before you eat them, too. Therefore, if you use Sevin dust on cucumbers, potatoes, or something else like that, you can safely eat them after harvest.

What Pests Attack Green Beans?

There are a few pests that are more common on green beans than others.

These include western spotted cucumber beetles, Mexican beetles, spider mites, thrips, and aphids.

If you’re trying to get rid of pests and prevent their damages, your first step should be to identify the pest you’re working with. Applying Sevin dust won’t be very effective if you don’t even know what you’re going after!

Cucumber beetles and Mexican beetles are closely related to lady beetles, but unlike lady beetles, they are not helpful in the garden. They feed upon plant tissue. Cucumber beetles are bright green with black spots, while Mexican beetles are copper-colored with black spots.

Aphids are small, feeding specifically on beans. They can be black or green and feed by sucking on plant juices.

Not only can they damage plants through this sucking mechanism alone, but they can also spread a variety of viral and bacterial diseases. Plus, they leave behind honeydew as they feed, which is a sticky substance that can attract hordes of ants.

Thrips are shaped like spindles and can be brown, black, amber, or yellow. They leave tiny black excrement behind as they feed and are most common in hot, dry weather.

Finally, spider mites are hard to spot, but may leave behind silk webbing that gives you an indication that these pests are to blame.

Other Pest Control Options for Green Beans

Fortunately, Sevin dust isn’t the only way you can control pests on green beans – although it’s often used as a last (and necessary) resort for many gardeners. Here are some other things you can try before resorting to chemicals.

Keep a Weed-Free Garden

Try to reduce weeds as much as possible in your garden. This can help prevent pests from laying their eggs and overwintering in the garden – plus, it reduces their hiding spots.

When plants aren’t competing with nearby weeds, they’ll grow stronger, and be able to resist the threat of pests a bit easier, too.

Use Row Covers

Row covers are incredibly beneficial when it comes to preventing insects from laying their eggs on plants. Cover up seedlings when they are the most fragile, then remove the row covers when it’s time for the plants to be pollinated.

Try Companion Planting

Companion planting is a classic technique that can work wonders in preventing pests. Certain insects are repelled by certain plants.

For example, you might try growing catnip near beans to repel flea beetles. Marigolds can deter Mexican bean beetles as well as many other insect pests (along with microscopic worms). Nasturtium and rosemary help deter bean beetles, too, as do potatoes.

Plant Resistant Varieties

If you have a known pest problem in the garden, it might be a good idea for you to plant pest-resistant varieties. Even those that are listed as early-maturing may be able to better withstand pressure from pests.

Rotate Your Crops

Don’t plant your beans in the same spot each year. Some insects lay their eggs in the soil – meaning as soon as those eggs hatch into larvae and develop into adults the following spring, they’ll have plants to feed upon immediately. You can avoid this by simply moving your crop to a new location in the garden each year.

Try Diatomaceous Earth or Kaolin Clay

If the idea of dusting your garden to remove pest pressure appeals to you, consider using diatomaceous earth or kaolin clay instead. Both of these are natural solutions that work well, especially when dry.

Diatomaceous earth is a product that consists of the ground-up exoskeletons of microorganisms. It has super sharp edges that won’t affect you, but are abrasive to insects. It cuts up their exoskeletons and dehydrates them pretty quickly. Like Sevin dust, it needs to be reapplied after a rain.

Kaolin clay is another natural mineral with insect control purposes. It produces a white powdery film that irritates most insect pests.

Try Hand Picking

Some pests are easy enough to control by simply plucking them off the plants, especially when the infestation is minor. Just pull pests off the plants and drop them in buckets of soapy water!

Use a Less Harmful Insecticide

Even something as simple as a mild surfactant (like dish soap) can keep most green bean pests at bay. Using unscented dish soap in a spray bottle or something like pyrethrum, neem oil, or Bacillus thuringiensis (a soil-borne organism) can take care of pests in a more eco-friendly way. A natural insecticidal soap can be helpful, too.

Ensure Conditions are Up to Snuff

Take a good, hard look at your plants and their growing environment. Are you giving them everything they need to be healthy?

Most of the time, plants can withstand pressure from pests if they are grown in fertile, well-draining soil and are given the water, fertilizers, and sunlight they need to be healthy. See if there’s anything you can do to improve the growing conditions.

Water, in particular, is something to keep an eye on. Plants are more likely to suffer from an intense insect attack when they are drought-stressed. Plus, if you water diligently, you can often knock insect pests off the plants with a blast from the hose.

Clean the Garden Up

At the end of the growing season, don’t just leave your bean plants in the garden to rot. Although this works wonders when it comes to fertilizing the soil, it allows insect pests and their eggs to overwinter.

Green Bean Pests – My Personal Dilemma

Having a little problem here as you’ll see in the picture.

Notice anything in particular? Yeah, HOLES, everywhere! My poor poor green beans, well, what’s left of them after the chickens had a field day scratching in this particular bed, have been pretty much obliterated by some unidentified munching creature. (The little tiny flying bugs all over the backs of the leaves, perhaps?)

I haven’t really been able to identify what kind of pest is causing my green beans to suffer – and while I don’t want to resort to Sevin dust, I may have to.

I’ve tried spraying the plants with organic insecticides like the ones I mentioned above, but the problem with that has been that it can’t rain for 24 hours after applying the spray… and it has been raining every other day for several weeks now! So, the sprays have done no good.

My mother-in-law suggested that I add some lemon scented dish soap to some water and spray both sides of the plant’s leaves with that… but like I said, it hasn’t stayed dry long enough for it to help. I’m about to dig all of these up and replant the bed.

I don’t love the idea of using Sevin dust on my plants, but it might be the only remaining option in order to have my poor green beans. The good news is that, as long as you wash the produce well, it will be safe enough to eat.

updated 12/13/2021 by Rebekah Pierce