Getting Rid of Scale

Getting Rid of Scale

Part of Ep. 603 Too Cold to Garden

Learn about Integrated Pest Management. UW-Madison Green House Director Dr. Mohammad Fayyaz explains how this method can control insect scales on plants.

Premiere date: Dec 19, 1998

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
We're at the Botany Greenhouses on the University of Wisconsin- Madison campus. And I'm with the greenhouse director, Dr. Mohammad Fayyaz. Mohammad, earlier you told me that you practice I.P.M. here. What does that mean?

Mohammad:
I.P.M. means Integrated Pest Management. It is a safe procedure, or method to control pests or insects. By doing so, we use beneficial insects, we even use birds. And also, we use good sanitation. If we're going to use any chemicals, we do not use any harsh chemicals. We use safer insecticidal soap or oil.

Shelley:
Well, one of the first things I was taught to control insects in my own home is to know what the insect is, identify it properly. We're going to talk about scale today. But is there a way I can use integrated pest management at home with my insects?

Mohammad:
Yes, at home or in all greenhouses, there are usually four or five insects that attack plants. These are aphids, white flies, mealybugs and scales. And today, we're going to look at the scales. As you see right here, along the stem, on the upper side of the leaf and on the under side of the leaf, those are the scales.

Shelley:
The brown things that look like bark?

Mohammad:
Right, those are the scales.

Shelley:
Now, that's the adult stage, when it's heavily armored, I know. They're hard to get rid of at that stage.

Mohammad:
Exactly. Usually, you know, there are two big groups of scales, armored and soft-scale. Armored are the ones have a hard shell or hard coating. They don't have that from the beginning. The crawlers or the baby, after a few days going out on the plant, they become static and they start sucking the sap out of the plant and they produce that hard shell. And that is the hard part, to get the chemicals to penetrate through that shell and kill the insect.

Shelley:
Okay, well, why do we want to get rid of these insects? What do they do to our plants?

Mohammad:
What they do, after locating them next to the leaf vein, they start to suck the sap out of the plant. They're after the sugar in the sap. But they don't use all the sugar in the sap. So, some of them, they excrete right on top of the leaf or under the leaf.

Shelley:
Is that what this sticky stuff is here?

Mohammad:
Exactly, this shiny area, and they call that honey dew. And later on, there are different species of fungi called sooty mold, that start using that sap or that sugar. So, these black patches, as you see on upper side of this grape jasmine, that cause prevention of the sunlight into the leaf. So, actually, they reduce photosynthesis. So, overall, we have a direct and indirect effect of that scale on plant. Direct is by sucking and weakening the plant, yellowing of the leaves, and also the foliation all dropping out of the leaves. And also, by preventing the photosynthesis.

Shelley:
With the sooty mold. Okay, so we know that we do need to get rid of them. So, what's the best way? What's the safest way to get rid of them?

Mohammad:
If you have a few of these scales-- if you have a hand lens at home and you look at the plant-- there's few of them, just physically remove them?

Shelley:
Pick them off.

Mohammad:
Exactly. If you have more than that--

Shelley:
Like this plant?

Mohammad:
Exactly. What you can use is insecticidal soap that you should use to get rid of these scales. And what you have to do is that you repeat that once every seven or ten days. Repeat it three times or four times, so you'll be sure you get rid of all of them.

Shelley:
Now, I heard there's an oil that I can use, too, if I don't want to use the soaps. What's that?

Mohammad:
Right, that's an ultra fine oil that they use. That's different than regular dormant oil.

Shelley:
Okay, so we don't use a dormant oil? That would actually hurt the houseplants?

Mohammad:
Yes, that causes burning of the leaves.

Shelley:
Okay, so we repeat either one of those, insecticidal soap or the oil, three times every seven to ten days.

Mohammad:
Exactly.

Shelley:
It should take care of the problem.

Mohammad:
Yes.

Shelley:
Okay, great. Thanks, Mohammad.

Mohammad:
You're welcome.

Shelley:
Remember, the first step to insect control is knowing your enemy. For instance, this isn't scale. Don't confuse this. These are spores, or the fruiting bodies that occur naturally on many ferns.

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