Not only are there holes throughout the leaves, the new leaves look strange. Sort of rusty and crinkled and deformed. I suspected slugs initially because of the shape of the holes, but I've never seen a slug or heard of one in these parts. None of the gardeners I know have ever seen one here. The plant is near a rose bush and I see black ants crawling on it periodically, I'm pretty sure they are ants and not sweet potato weevils, but I could be wrong, I suppose. Any help would be much appreciated!
The first thing that comes to me is Japanese beetles, those sure look like the holes that they leave after they've been dining. Have you seen any on the plants? They can remain on the plant from early-ish morning into the afternoon, so you don't have to sneak up on them in the dark to find them. ;) Often, you should be able to find them during mid-morning to early/mid-early afternoon. Japanese beetles can not only put holes in the leaves that look like what you've got, but they can also really mess up new and newly-forming leaves as well. [I had a problem with them on my Agastaches earlier in the season; ended up knocking them off, gathering them, then enjoyed a collective squish session]. =)
Is there any chance your rose bush has aphids? If you're sure those are ants and not weevils (look for the tell-tale long narrow "snout"), it could mean that aphids are not far behind (or away).
Looks like aphids on your new leaves, which would explain the ants. The large holes are probably from paperwasps, they bite the leaves, chew them up and make paper for their nests. The damage is pretty much aesthetic and wasps eat bugs so I leave them alone. There is also a sphinx moth caterpillar which eats sweet potato leaves, but never does enough damage to hurt the plant since sweeties grow so fast.
Vossner, mine too look like swiss cheese in the heat of summer. I couldn't figure out what was making the holes and one day while weeding I noticed a wasp flying in repeatedly. I watched him/her and it could cut out a chunk of leaf in a flash and take off with it and be back for more in short time. I found the sphinx moth cats when I was pulling the vines for harvesting the first crop this summer. There weren't enough of them to be a problem so I left them alone.
Thanks for the input, I don't think that the culprit is Japanese beetles (I sure hope not anyway). As far as I know, they have never been found in any county near me. Very few have been found in Montana, so far anyway. I've never seen any aphids on my rose bush, but I suppose I should check it. I haven't noticed paper wasps either, but that also sounds plausible. I will investigate. Thanks!
You're welcome... and I guess I should have paid more attention to your area... makes a lot less sense that it would be Japanese beetles where you are. Silly me! < =/ (but GOSH those holes sure do look like it, LOL!!)
Keep us posted please on how the babies are coming along, I hope you're able to solve the problem in short order. :)
Hello, my potatoes are devastated! My neighbor has a wasp nest and she claims they pollinate the plants. These wasps tend to come directly to my potatoes and create lots of holes on the leaves. I just took a picture of one of the wasps that stayed still long enough and want to figure out if this is the paper cutter or the yellow jacket. I know for sure that the paper cutter will not pollinate and if this is indeed the one, what is the best way to deal with my neighbor or the wasps? Thanks.
I'm not 100% sure, but after perusing the Bug Files pics, it sure looks like a paper wasp to me, possibly the European one..?? Take a peek at the Bug Files, type in "wasp" to search; the European paper wasp is about 1/2-way down page 1. If it's safe for you to do so, could you try to take a more close-up pic? That might help to identify it more surely.
Here in SC, the ones I have in hanging pots don't have these holes; however, the ones I planted in the ground have them. So, I thought it was slugs & sprinkled snail& slug bait around them. But the holes kept on coming LOL When I went to the local nursery, I saw that their sweet potato vines had the holes. So, I asked them what was causing the holes, and I was told it was an annoying pest call the Flea Beetle. You might want to check to see if they are in your area.
Is your SP plant an ornamental or the eating type? Did you plant it from a slip? If so, did you grow the slips?
Often in a slip bed, when the slips are tender and crowded, which they usually are, the Golden Tortoise Beetle will be. After the slips are transplanted to the garden or SP field, are not crowded and start to grow, temperatures increase, leaves toughen, and this insect usually disappears. The damage it leaves behind is minimal, I have found.
They are small. You really have to look for them. They are pretty.
My Morning Glories have the same look- like swiss cheese. I found a beautiful shiny gold beetle- the Golden Tortoise Beetle. At first it didn't seem to be a problem, but soon I found lots of little black lumps between 1/8" and 1/4"on the leaf tops and lots more holes. Look closely. These are the larva. They carry their feces on their backs. I'm brushing the larva off into a bucket of soapy water and hoping for the best!
Would neem oil be a decent discourager on these plants? I've read that it not only kills some pests that eat it - aphids, for instance - but that pests will avoid neem-treated plants in favor of other choices. (It even helped protect a hibiscus that a rabbit almost completely defoliated in two nights flat; regular neem for the rest of the summer kept the rabbit away, from that plant at least.)
I have *not*, however, noticed that neem is able to kill or even discourage Japanese beetles, in spite of claims to the contrary on the web. I wonder, if it's wasps, if they would be repelled. Worth a try, perhaps.
I have only seen Neem oil effective when applied directly to Japanese beetles. And it can take a couple of applications to get them.
But it doesnt seem to discourage them. The Neem oil does not seem to provide any residual control of any insects that I know of. But repelling? Could be. I have been regularly spraying my blackberries with Neem and I havent had as many wasps eating the fruit.
Well girls, I have a new problem. My potato vines have a small black spot where the leaves and the stem meet. I can wipe it off with my finger but I'm afraid it is some fungus or ??? Can you tell me anything about this? Alda