Usually it's too late to treat by the time you see the damage. It happens in cycles. Even if you used a systemic pesticide, there would be damage before the pest died.
Late summer seems to be an unusually bad time. Holes show up on the inside of the leaves, not on the margins.
Something was eating the sweet potato vines in my yard all summer. I could never see any bugs during the daylight hours so I'm assuming it's some nocturnal buggers chewing on them. I dug out many of the tubers a couple of weeks ago because they were taking over everything and looking awful with all the holes chewed in the foliage. They are like weeds down here, growing wildly and trailing all over the flower beds.
Some blame grasshoppers, but they usually chew on the MARGINS of leaves, not the inside part. And the holes in ours are nicely cut out, while grasshoppers chew and leave ragged edges. Most people say it's slugs or snails, but they'd have to be young and lightweight, because the leaves are fragile and floppy. The damage looks like caterpillar damage, but I thought most moths and butterflies were through reproducing for this season. I guess it could be different varmints in different parts of the country. They seem to love the Marguerite best, and it looks worst because the holes in that chartruese show up so much.
As far as them taking over everything, that's where the new series Sweet Caroline come in. They are much more compact (short internodal spaces) and not as weedlike in their growth habits. Try them- you'll love the difference. They come in about a dozen varieties.
I'm going to take up my tubers for the winter soon, too. The leaves are so chewed I don't enjoy them anymore. Did you know that if you put the tuber in a shallow pan of water submerged an inch or so, maybe less, (next spring) little plants called slips will develop on the upper part? When the slips get big enough you can pot them and have many new plants. You just gently lift them off the tuber when they are big enough to pot. Just don't expose the tuber to freezing temps during the winter.
LOL, I didn't take up the tubers for winter, I dug them up and threw them out because they take over everything! I love the looks of them in containers but it doesn't take long for them to trail out of whatever container they are in and run wild all over the yard!
I will have to check out the new Sweet Caroline series ... I have not heard of them, but if they are more compact and not as weedy, I would love to grow them!
tcinmb- I keep threatening to go out and check the plants at night too, but have yet to do it. Please let us know.
I forgot to mention, about growing the slips- you would think the s.p. tuber would rot sitting in water, but it can sit there for MONTHS and not rot.
I remember many years ago learning to grow a sweet potato plant and an avocado plant in water. Take two toothpicks, stick one in each side of the tuber and sit it on top of a glass or glass jar, (the toothpicks lay on the edges of the jar to keep the bulb from falling into the water. Fill the glass jar just so the water level barely touches the bottom of the tuber. Eventually it will put out roots and the potato vines will begin growing out the top. With the avocado you stick the toothpicks in the avocado seed and do the same thing, roots will sprout and eventually you will see a little sprout from the top of the bulb and you can grow a nice little avocado tree houseplant!
When I was a boy, people didn't know what it was to buy houseplants. Ladies would put a sweet potato in a jar with a diameter smaller than the potato and grow a vine for the kitchen. Sometimes the vine would get so long it would turn the corner and grow along the next wall.
The vines were pretty enough, but if they could only see Marguerite, Blackie, Ace of Spades, Tricolor, and now the Sweet Caroline series!!! Bewitched is the queen of them all.
I cut my sweet potato plant back, took off the bottom leaves. Then diped the leaves in clorox water(1tsp to a gal. water, to get rid of any bugs). Put them in a jar to root, (in a shady place)now I will plant them and bring them in for the winter. As they get bigger this winter I will continue to cut them back and root more. By spring I will have plenty to plant in my hanging baskets.
All I've ever done was stick a sweet potato in a glass or jar of water about half way and watch the vine grow. They have always done well for me and when you get tired of the plant you can plant it in the spring and have lots of sweet potatoes in the fall.
... used to do that all the time as kids. Wedge a sweet potato in a glass or jar so the bottom half is in water & watch as it took off, growing like crazzy! Sometimes we'd stick toothpicks in the sides to keep the potato from falling into the container.
Not to hi jack your thread but I wanted to share this, I had mine in a large pot and a ground hog made a meal of it so I dumped what was left and lo & behold it gave me a present. I plan on cooking it up this weekend to see how it tastes...
I was amazed with the results for my sweet potatoes. I took cuttings in late spring (planted in early spring) and the took off. They were placed in a glass of water with some rocks to root. After 3 days i checked them and spotted roots. They rooted remarkably fast! Has anyone else had these results???