New Insecticides For Gardeners

New Insecticides For Gardeners

Part of Ep. 1703 Ideas for Spring

Discover new insecticides from UW-Madison Extension entomologist Phil Pellitteri. Insecticides based on plant oils include clove, peanut, soybean, wintergreen and sesame seed oils. Other products include Diatomaceous Earth, Spinosad, Neem oil and natural chemicals like piperonyl butoxide, pyrethrum and 2-phenylpropionate. Pellitteri also explains why a natural product isn't necessarily organic.

Premiere date: May 06, 2009

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
Every year new products come out to help us in the garden.  Some are wonderful, and then some are more confusing.  I'm with UW Extension entomologist Phil Pelliteri to learn what works, and how to use them.  Phil, there's always new products out there.  We need to know how to use them and how not to use them.

Phil:
One of the interesting things, Shelley, is that there's a lot of new products that are coming on the market that are both natural and organic.

Shelley:
Yeah, those are the buzz words.

Phil:
And here I have a product that contains clove oil, it also contains a product called 2-phenylpropionate, which sounds like a real scary chemical.

Shelley:
Yes, it does.

Phil:
It's derived from peanut oil.  And the good news about that is it doesn't cause allergy problems.  There's also soy bean oil and wintergreen oil in some of the products, this particular product is for indoor pesticide use, so you'd use it against ants and roaches and those kinds of things.

Now, what's going on is, there are a lot of products that are natural food additives that have insecticidal properties.  These are what are coming on the market.  One of the differences is because they are food additives and they run through the FDA, they don't go through the normal process, so we don't necessarily have as much data on how they work.
But in general, the way these natural oils work, we know that oils suffocate insects, so that's one thing that's going on.  But there's more to it than that.  The products that have the most activity have some neuro-toxic effects on insects but not us.

Shelley:
So we don't eat these products, but we eat the food products they originate from.

Phil:
Oh no, we eat these products.  They don't have those kind of effects in people, but they affect the insects.

Shelley:
Wow.

Phil:
There's a lot of them here.  Here's another one that has sesame seed oil as the base product.  Now, the way to think of these oils is as a contact killer.  Almost any insect would be affected.  I will tell you, though, that hard-skinned things like beetles don't often respond quite as well as other things.

Shelley:
To a lot of these oils.  So these are all the smothering kind of groups.

Phil:
The other thing is, we tell people it's best to use the stuff that's registered as this, not to go and get stuff out of the kitchen.

Shelley:
Like sesame oil for cooking.

Phil:
There's problems with dilution rates, there's problems with impurities that might cause plant problems, so that's one thing I think I'd be a little cautious about.

Shelley:
So when we say we eat these, we eat the food products from the grocery store, where we would never play with these.  These have other things in them.

Phil:
Well, I usually figure that these things are purer but these things are not the kind of things - you don't want to mix cooking oil with the stuff that is refined to use as a pesticide.  Now this one is gonna be a little bit confusing to people.  It contains pyrethrum which is a naturally-occurring insecticide that we've used for centuries that's derived from chrysanthemum.  That's organic.  And canola oil.  So you'd say, boy this is organic.  Well it turns out, it's natural, but it's not officially defined as organic.  And the problem is that some canola oils are from genetically modified plants.  And by definition, organic cannot contain things that people have manipulated, so this would be an example of a natural product that is not organic.

Shelley:
And let's talk a little bit about that.  So, organic means nothing synthetic.  Natural means...?

Phil:
It's derived direct from nature, but at times you can get these complications.  Another example is the pyrethrum, natural from chrysanthemums.  Many times when you buy fly sprays with pyrethrum, it has an additional product called the synergist.  And the name of this product is piperonyl butoxide, or we call it PBO for short.  It turns out that's a synthetic compound.  If you mix a natural product with a synthetic product it's not organic anymore.  It is still a reasonable product to use, but if people are looking at the pure definition that USDA uses, if it has some of these additives, that throws it right out.

Shelley:
Well, and the thing people need to remember, too, is just because it's organic doesn't mean it's completely safe.  You can still misuse something, you have to read the label.

Phil:
We always tell people that every pesticide has a personality.  If it kills things it has to have some mode of action, some toxicity, that you have to pay attention to.

Now this product is called Neem oil, and this has been on the market for a while, it's derived from a tree that grows in Africa and India, and they extract the seed and get what is almost magic potion.  This stuff is used as an insecticide where it makes things taste bad.  It also will have some hormonal effects on insects and may kill them.  This is one of my favorite products for Japanese beetles.

Shelley:
Ooh, I'm keeping this.

Phil:
Part of the reason is, it has a broad label, we can use it both on edible crops and on our ornamental crops.

Shelley:
So, the vegetables.

Phil:
Right.  The other thing is there's no harvest restriction in most cases.  You always have to look at the pesticide label, if something's registered there, if it's put on edible crops you usually have to wait a certain number of days.

Shelley:
14 days, or whatever.

Phil:
And this stuff has a zero harvest time.  So we're using it on grapes and raspberries.  The problem with raspberries is they're just starting to fruit when the Japanese beetles show up.  You want to be, of course, very careful.  This is a product that's also used for other purposes.  They use it for hair oil additives, people use it for toothpaste-like products.

Shelley:
Really?  It's the magic one!

Phil:
Almost sounds like snake oil.

Shelley:
But read the lable, anyhow.  Now this one is really wild.  This product is called Spinosad.  It's a new pesticide that's been on the market for about three years.

Shelley:
What kind of insects?

Phil:
Well, it kills caterpillars, it kills thrips, and it's pretty good on some beetles, including Colorado potato beetles.  So that's neat, because most of our pesticides don't work against that particular pest.  What I find the most fascinating is the derivation of this.  This was discovered, it's a fungus that grows under rum stills in Jamaica.

Shelley:
All right, who was crawling under the rum still in Jamaica?

Phil:
I think some scientist was on vacation, he took a soil sample, brought it back to the lab, and we have been mining the world looking for new types of insecticides, and lo and behold, they found one here.

Shelley:
Wow.

Phil:
One of the things is, it doesn't kill everything.  If you have an aphid problem, this would not be the proper product.  Those kind of things, that's why you read the label to see what kind of insects are listed on there, what crops are listed on there, and if it's not on there, it's not legal to use it.

Now the last one is a product that has been around quite some time, but I find that people don't quite understand.  It's called Diatomaceous Earth It's a natural insectide that is mined from things that are in the soil.

Shelley:
It's like fossilized stuff, isn't it?

Phil:
I think of this almost as a very fine sand.  That's really the way it is.

Shelley:
It's gritty.

Phil:
When insects crawl across it, it abrades the surface of their body and they honestly die from drying out, desiccation.  The problem, though, is how you use it.  You mix it with the soil, you put it on your plants, it gets so diluted or gets blown away.  It's not there to do its intended purpose.  Where these products are most effective is indoors.  If you've got ant problems, if you've got cockroaches, we're even using it for bedbugs, where we place it back in the cracks and crevices where these things hide, and one of the advantages of this product is, it doesn't degrade.  It's there all the time until you wash it away, so that's really nice.

Shelley:
So in my house it's there forever.

Phil:
It's a natural product.  I always tell people, I can kill any insect in the world if I put it in a container with diotomaceous earth.  But there are limitations outside.  As I said, you can't confine the diatoms, they just blow away, it's like a dust.

Shelley:
Okay, so it loses its concentration basically.  Well that's good to know, too, then.  I've been using it outside where it's not effective, so I learn something every time.  Well, thank you, Phil.  I'm going to read the labels and I think I'm going to go get some Neem oil.  Thanks.

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