How Long Does It Take Sevin Dust To Work?

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There are few things more frustrating than putting your blood, sweat, and tears into your dream flowerbeds or luscious vegetable garden only to find it ravaged by insects, worms, and other pests! They have declared war on your produce, so it’s time to pull out your Sevin Dust insect killer to take care of the problem. But will the Sevin get to the pests before your leafy greens perish?

Sevin Dust pesticide affects insects immediately upon initial physical contact and most effectively through consumption of the poison. It takes between three days to several weeks to eliminate the pest population but remains active for up to three months after the first application.

If you would like to learn more about Sevin and how to use it to help your garden, keep reading. Some things about it might surprise you.

How Quickly Does Sevin Dust Work?

According to Altine from Plant Heaven, the Sevin Dust will start working its neurotoxin magic on pests once they touch the powder, but since it takes time for the entire colony of vermin to make contact with the plants, you won’t be able to see how effective the dust truly is for at least several weeks. However, you should still be able to start seeing results after several days. According to Garden Tools and Instruments, the Carbaryl will begin to break down into a harmless residue after 3 ½ days.

Sevin Dust is also quick to use as you don’t have to measure water or mix the insecticide. All you need to do is sprinkle the dust on the areas of the plant that is being eaten such as the stems, the soil if the roots are being eaten, or the leaves. Putting the dust on blossoms is not advised because you are much more likely to poison the pollinating insects that you want.

What is Sevin Dust?

For gardeners new to this product, Sevin Dust is a pesticide that uses the chemical carbaryl to kill insects. It promises to kill 65 different pests and while it’s meant for gardens it’s commonly used for lawns and golf courses too. It works by disrupting the insect or pest’s nervous system to prevent vital bodily functions. In other words, it’s a neurotoxin. Sevin works best on insects when ingested, so it’s most effective against chewing insects and worms.

As far as pesticides go, it isn’t extremely dangerous (the bigger you are), but it can easily become lethal. According to retired extension agent, Mike Dennison’s research, the Lethal Dose required to kill half of the test subject population (LD50) for Carbaryl is 500-850mg per kg of body weight of the test subject. So, if you had a bunch of 1kg rats, you would need 500-850mg to kill half their population.

What Insects Does Sevin Kill?

Sevin boasts of being able to kill 65 different insects, but this is accumulative for their products. To be certain your Sevin product will kill your intended pest, look on the back of the label to see the list of pests that particular product targets. GardenTech provides a general list of insects Sevin Dust controls. These are:

  • Ants
  • Armyworms
  • Fleas
  • Spiders
  • Flea Beetles
  • Japanese Beetles
  • Imported Cabbageworms
  • Leafhoppers
  • Stink Bugs
  • Cucumber Beetles
  • Chiggers
  • Ticks
  • Squash Bugs
  • Earwigs
  • Spittlebugs
  • Tomato Bruitworms
  • Colorado Potato Beetle
  • Strawberry Weevil
  • Raspberry Aphid
  • Periodical Cicada
  • Lacebugs
  • Rose Aphids
  • Rose Slugs
  • Tent Caterpillars
  • Fall Armyworms
  • Millipedes
  • Sod Webworms
  • June Beetles
  • And others specified on the labels

Are There Unintended Victims?

Sevin is an effective insecticide. However, poison can’t distinguish between intended and unintended targets. Some unfortunate victims might not be insects at all!

When Sevin is washed away by human watering or by rain, the Carabyl can mix with the water, and through the water cycle, become contaminated rain, according to the United States Geological Survey (USGS).

This widens the list of affected wildlife to include

  • Ladybugs
  • Butterflies
  • Honeybees
  • Bumblebees
  • Leaf-cutter Bees
  • Alkali Bees
  • Frogs
  • Salamanders
  • Freshwater Fish
  • Other Aquatic Invertebrae
  • And Jumping Mice

The amount of damage will of course depend on the size of the creature and how much carbaryl found its way into their system. As I mentioned earlier, it takes a considerable amount of carbaryl to be lethal for creatures larger than a spider.

As Paracelsus once said, “All things are poison, and nothing is without poison; the dosage alone makes it so a thing is not a poison.”

How Do You Use Sevin Dust?

Sevin can be applied as dust, a liquid concentrate, granules, and a wettable powder. The difference between the dust and wettable powder is that the dust should NOT be wetted after applying because it will simply wash away.

There are a couple of things that affect the effectiveness of the dust: wind and water. For the best results, GardenTech advises not to apply when rain is expected within 48 hours. If you have automatic sprinklers, be sure to turn those off for the day. Plant Heaven suggests waiting 24 hours before watering your garden again.

You don’t want to apply it on windy days either. Not only does it just blow the dust away, but the dust could go where you really don’t want it to, like inside your home. If you apply it to plants in a greenhouse or shed, be sure there is proper ventilation so that you don’t breath it in.

Now, although Sevin Dust shouldn’t be watered after application, it’s advised to water your garden before applying the dust. That way, your garden is watered and the dust is less likely to be blown off.

Whatever form of Sevin you use, it should always be applied with gloves and a mask at the very least to prevent ingestion or absorption through the hands. For the best protection, wear jeans without holes, a long-sleeved shirt, and goggles.

How Much Dust Do You Use?

How much you apply depends on the percentage of insecticide it contains within the mixture. The label will let you know how much the company recommends you use and how often to use the pesticide.

Sevin 5% is the most commonly used Sevin Dust product for houseplants and small gardens. Its label says no more than 7 applications per year. No particular amount of Sevin Dust is prescribed, Instead, you’re instructed to apply a thin layer of dust evenly. It’s important to note that SFGate does not recommend using the dust more than once within seven days.

For wettable powders or liquid forms of Sevin, Joe Masabni from the University of Kentucky has very helpful measurements for whatever sized garden you have. If the directions on the bottle are for 10-gallon mixes, he will provide calculations for how much pesticide to use for 1 gallon.


In conclusion, Sevin Dust is a very effective pesticide that is remarkably quick-working. But before you buy as much as you can carry, Mike Dennison made an important observation from his experience with carbaryl.

He noticed one year that it took 8x more of the poison to kill a flea than it did only a few years before. Carbaryl has been in use since 1959, so we shouldn’t be surprised if many insects have developed an immunity against it.

If you have any other questions about Sevin products, you can check out the links in this article, the Sevin company website, or ask your local gardening experts to help you.