Oregano with aphids--Disease?

10 years ago

My oregano needed to be trimmed, I will point that out first. It had gotten pretty big. I knew it had an aphid problem, which I was trying to quell with garlic spray.

So here's the deal. Not surprisingly, there were still aphids living on the inner part of the plant. As I was cutting it back, I noticed that a lot of the younger stalks that were growing out of the center of the bush were all yellow and mottled looking. It looked a little like early blight, only the entire leaf was yellow, and they had some black spots on them. It appeared isolated--that is to say, the "diseased" area seemed to be contained on each of the stalks that were affected, but none of the other stalks appeared to have the beginnings of any kind of disease. It was basically a healthy looking stalk here, a yellow stalk there... does this sound like disease? Lack of sunlight being so buried within the plant? Overall lack of health of the plant due to aphid infestation?

FYI, I have also found a few grubs and slugs in there too, but primarily it is an aphid problem. Either that or some sort of mite. Honestly, I'm a novice, so I'm not sure I'd be able to tell the difference. Whatever they are, they sit under the leaves, but also on top of them. So basically all over the leaves that are affected. Do aphids only live under the leaf?

The oregano plant is near my sugar peas, some sage, and some bush beans. So far they appear to be unaffected by the oregano problems. I went ahead and used the garlic spray on all of them, just to be safe. I also sprayed the tomato and squash, which are separate, but I just decided to be thorough.

Sorry this post ended up being so long. I cut the oregano all the way to the "stump" and disposed to the branches. The plant is on its fourth summer in the same location, so I can't say I'm surprised that it has developed a pest problem. Should I remove it altogether?

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Comments (9)

fatamorgana2121
10 years ago
Where are you? I generally only see much in the way of aphids here indoors or before summer gets into full swing. Once the weather warms, I see occasional aphids depending upon the plant type but its never a huge deal. And especially not on oregano. But if they are a huge problem for you, look into getting lady bugs. They are aphid eating machines.

Grubs and slugs? Just part of the great outdoors. Squish 'em. There are also metal barriers and traps for slugs. The beer traps do work well.

I don't think you have huge problems but if you want to share some pictures, it might help share what is happening.

FataMorgana
wally_1936
10 years ago
I hope you are adding a drop or two of dish soap to your garlic spray.
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jemsister
Original Author
10 years ago
Yep, my garlic spray has dish soap. Some recipes also say to add peppers, but that sounded harsh for spraying directly on plants...

I don't understand why, since herbs always seem so hardy and low maintenance. But the oregano was absolutely covered, and I could not for the life of me figure out why it was being so attacked. I cut it all the way down to virtually no foliage, and then sprayed it a whole bunch again, so hopefully that will completely eradicate the problem. If not, I'm going for ladybugs.

The yellowy/black leaves on the inside parts of the plant do concern me a bit.

I live in western Washington--Snohomish county, so on the northern side. Very damp here, and we don't get much higher than 80 degrees in the peak of summer. Springs tend to be pretty rainy and hang out in the sixties...

I used beer traps for slugs a few years back, and they worked perfectly. If they become a problem again, I'll put out more again. So far the slugs and grubs haven't really done any damage.

This post was edited by jemsister on Fri, May 17, 13 at 15:17
jemsister
Original Author
10 years ago
Here are some pictures of the plant.
jemsister
Original Author
10 years ago
Mottled leaf.
fatamorgana2121
10 years ago
Too much water is probably at the heart of your issues. Don't water it. These can take pretty dry conditions. If you have an extended drought or heat, water it. Else do nothing.

And sometimes leaves that were shaded by the rest of the plant (now gone in your case) are pathetic and yellow. The new growth under it looks just fine.

FataMorgana
jemsister
Original Author
10 years ago
I don't water it, but we do get a lot of rain here. Maybe that's the problem. Hopefully it will perk up when we get some sun. It's never responded to the rain this way. =/
zzackey
10 years ago
When did you last fertilize it?
wally_1936
10 years ago
It has no problem here in Texas mine went from a 3 inch pot to 3 X 3 foot plot in 2 years. Ended up sharing with a few friends. Our hot and dry climate seems to agree with them. As for aphids I use a drop of dish soap in my bottle sprayer and that kills them along with any ants it touches.

This post was edited by wally-1936 on Tue, May 21, 13 at 8:46