Spinosad spray: what it’s and how you can use it

One of the most frustrating aspects of gardening is dealing with insect pests, which can frustrate some home gardeners into the point of giving up. Before you toss the trowel once and for all, it is necessary to hear about spinosad spray if you are not already familiar with it. It's an organic form of pest control that is derived from a bacterium called Saccharopolyspora spinosa and, with the exception of a few beneficial insects, does not pose a major threat to nature.

You may have heard of Bacillus thuringiensis or BT which is another godsend for organic gardeners. There are many pests that BT cannot kill, and spinosad spray will kill most of them. If you use both together for your vegetables or other products, your garden will remain almost completely pest-free. Spinosad is highly toxic to bees when wet, so you need to be strategic about the time of day that you use it. But once dry, it can kill chewing pests for up to four weeks!

If you want to know more about this magical spray called Spinosad, we tell you everything you need to know about it, including how to use it.

What is Spinosad?

Applying Spinosad spray will reduce pest pressure in your garden. Source: Oregon State University

Spinosad is made up of chemicals called Spinosyn A and Spinosyn D. While it may sound unnatural, these chemicals are extracted from the fermentation juices of soil bacteria, which means that the product is obtained completely naturally. Spinosad is a relatively new insect killer that was approved by the US EPA in 1997. In 2003 it was officially awarded organic status by the USDA National Organic Program (NOP). With these seals of approval you can safely use them in vegetable gardens and on your ornamental plants.

Since spinosad is natural it can be safely applied to food crops, but you should keep the habit of washing all of your food after harvest just to be safe. You can spray it on leaves or fruit, or anywhere you spot insect pests.

The most popular form of Spinosad is a spray that is applied directly to the plants and dries within a few hours. It is also available in the form of dust and granules. Dust may be easier to find than granules, and granules are usually sold as fire ant killers. Ant killers usually contain a bait so that the ants ingest the granules and put them in the nest, so it may not be suitable for organic horticulture. You may find other synthetic pesticides that list the active ingredient spinosad in them.

How does Spinosad kill insects?

How does this miracle product work? Saccharopolyspora spinosa is toxic to pests and affects their nervous system. Once spinosad is applied to the plant, insect larvae feed on the substance and die within a day or two. Spinosad causes the insect's muscles to flex uncontrollably, causing paralysis and ultimately death. It's most effective when the larvae eat it, but simply walking over it is usually enough to do some damage.

Spinosad can kill a wide variety of insects, including fire ants, fruit flies, leaf miners, mites, mosquitoes, spider mites, and thrips. This relatively new insect killer is generally used with other garden species on vegetables and fruits. Many organic gardeners use BT to care for caterpillars and use Spinosad spray for everything else.

Keep in mind that this garden insect spray can harm beneficial insects like bees, but we'll get into the details in a moment.

Benefits of Using Spinosad

Structures of Spinosyn A and DDiagrams of the chemical structures that make up spinosad.

There are more benefits than dangers to using spinosad, so you should probably have this insect killer on hand if you aren't already.

An obvious benefit is that spinosad kills insects that BT does not, such as thrips, flies, and fire ants. The best part is that it lasts a lot longer than BT. It can last up to four weeks unless it's washed away by rain or the garden hose beforehand. When a liquid spray can last that long, it's hard to say no!

A key benefit is that, unlike synthetic pest control chemicals, because it is a natural substance, it does not have a negative impact on the environment. The two chemicals that make up spinosad come from the fermentation juices of bacteria, so you fight nature with nature. It's OMRI listed as organic, which means it's classified as organic by the Organic Materials Review Institute.

Spinosad is quickly broken down by sunlight and water and disperses in the soil so you don't have to worry about it polluting the groundwater or the soil. Some chemical pesticides can linger in the environment for up to a year, causing them to accumulate in the soil and groundwater. Fortunately, we don't have to worry about that at Spinosad. Remember that it came from the earth and so it just comes back home!

Disadvantages of using Spinosad

The biggest disadvantage of spinosad, which can deter home gardeners from using it, is that it is highly toxic to bees when the spray is wet. Timing is everything when it comes to Spinosad. Bees are most active during the day, usually from morning to late afternoon. Use Spinosad spray in the evening or very early in the morning to allow enough time to dry. It shouldn't take more than three hours for the spray to dry completely.

Since spinosad spray is considered safe to be near bees once it dries, the dust and granules can also be considered safe. Even so, you should wait until the bees are no longer active to take precautionary measures. Take the extra step and avoid applying spray, dust, or granules to flowers or other places where bees frequently land.

Another problem is that spinosad is moderately toxic to earthworms. You can avoid worms by applying it to plants only when needed. Using granules to treat fire ants is sure to put the worms at risk, so try not to use them near your garden beds or in any other location where you want to keep the worms safely.

Finally, Spinosad is slightly toxic to humans, animals, birds and fish. This toxicity is incredibly low. Contact with skin or eyes should only cause irritation and redness. Animals can have a similar reaction if they should come into contact with it.

When using Spinosad, avoid touching your skin. Wearing safety glasses when applying, especially if you are using it in dust form, will keep you safe and protect you from irritation. Be careful when and where you use it so you can protect worms, bees, and other animals. As long as you follow these guidelines you will find that Spinosad is not that dangerous to work with.

How to use Spinosad

Spinosad powderSpinosad in powder or dust form is less common than spray, but just as effective.

Spinosad liquid spray comes in two forms, ready-to-use (RTU) and concentrate, both of which you should find in the gardening section of the hardware store. One brand readily available is Monterey Garden Bug Spray, but there are many other options in the market.

RTU Spinosad sprays are easiest to use in the home garden because you can start spraying immediately after opening the bottle. It doesn't require mixing or measuring, but you should still read the label on your RTU product to make sure you're using it correctly.

Spinosad concentrates should be mixed with water before using on plants. Mixing it with water dilutes it to a safe amount so you won't harm the wrong bugs or yourself. The exact dimensions can be found on the product label. You need to measure out the correct amount of liquid and mix it with water. It's usually a few tablespoons per gallon, but this may change depending on the product. Once it is properly dosed, you can start spraying it on your plants as directed.

For both types of Spinosad liquid spray, you should apply it to the top and bottom of the leaves as well as the stems. You should spray it anywhere you see pests and larvae. Remember not to spray flowers to protect the bees and avoid spraying the soil if you can. You can spray larvae directly, but when they eat sprayed leaves you will find that it is most effective. If you see eggs on your plants, you will need to spray again a few days after they hatch.

Spinosad dust is supplied either in a bag or in a collapsible container. When you have the container, just squeeze it to get the dust out and apply it to the top and bottom of the leaves like a spray. It may be a little more difficult to use if it comes in a bag. Find a squeezable container that you can clean and reuse to apply Spinosad, or put on gloves and spray with your hands. Regardless of the packaging, to avoid skin irritation, wear gloves and cover your arms to reduce exposure when handling dust. It is advisable to wear a mask as well to avoid breathing in the dust.

Spinosad granules are easy to apply because you just need to spread them evenly over the floor. Follow the directions on the label to find out how much to apply to a specific area. Since it is widely used to control ants, you will likely find the ratio for how much to apply per 1,000 square feet. So you may need to know the size you want to apply it to and pull out a calculator. If you apply the granules by hand, be sure to wear gloves to avoid skin irritation.

Although dried spinosad is safer for beneficial insects than when wet, as an additional safety precaution, wait until the evening or early morning to apply dust and granules so that you can reduce their likelihood of exposure.

frequently asked Questions

Q: Which insects kill Spinosad?

A: Spinosad kills several types of pests, including caterpillars, fire ants, fleas, fruit flies, leaf miners, lice, mites, mosquitoes, spider mites, and thrips. Be careful when using spinosad spray as it can be very toxic to beneficial insects like bees while it is still wet.

Q: is spinosad harmful to humans?

A: The active ingredient spinosad is only slightly toxic to humans. If it touches your skin or eyes it may cause redness and irritation. The effects are seldom, if ever, worse. You will most likely only come into contact with small amounts of it, which is not much cause for concern.

Q: When should I spray Spinosad?

A: Since Spinosad (Saccharopolyspora spinosa) is highly toxic to bees, the best time of day to spray Spinosad is in the evening or early in the morning when the bees are not active. It remains toxic for about three hours or until completely dried. So it is wise to learn when the bees come out so that you have the right time to spray.

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