Friday, June 25, 2010

What’s Bugging the Garden Spot? Three Lined Potato Beetle

My poor eggplants are having a rough time. First slugs attacked the bottom leaves, and then something else began munching on the upper leaves tearing ragged holes:

 I’ve been carefully examining the plants every day to try to spot the culprit. I think I found it:

This is the Three Lined Potato Beetle. It feeds on plants in the nightshade family, including potatoes, tomatoes, and eggplants. They are pretty quick at hiding by ducking behind leaves, dropping to the ground, or taking off as I approach. I spotted a few of these last year, but they never made much of an impact. 

I am growing potatoes for the first time this year, and believe in doing so is attracting more nightshade pests to the garden.

Once I was able to identify the pest on the eggplant as the Three Lined Potato Beetle, I looked at the potato plants more carefully and spotted a few in the potato patch as well:

I found the easiest way to exterminate these is to use a container of soapy water. Place the container under the beetle and hover your hand above, palm side down. The beetle will not be able to fly and will instead drop from its perch directly into the soapy water. The eggs are found on the underside of the leaves, I also place the soapy container beneath them and scrape them off with a stick and dip it into the soapy water. Or just pick off the leaf and dunk it into the soapy water.

Not a huge infestation on the potatoes, but close examination of the leaves will have to commence from now on in order to seek and destroy any further eggs that are found.


  1. Gardening can drive one buggy at times! I found a huge beetle on the snow peas this morning when I was pulling them out. It was a grapevine beetle...over an inch long! There are no grapevines in this neighborhood. I showed it to my grandson and then we relocated it...far away from our house

  2. Maddening ! Good thing you found them in time. They were really going to town on your eggplants ! Will definitely be on the lookout for those on both my spuds and eggplants. Thx !

  3. Yikes, that is good you found those beetles. Something has been eating the leaves on our broccoli. And one entire was destroyed.

  4. Good for you! Although it's harmful to the garden, I think it's kinda cute. (never seen one before)

  5. We get those guys here in Wyoming too!

    I'm battling grasshoppers right now... grrrrhhh... next year I'm going to get chickens or muscovy ducks... just to help me deal with them!

    I love the new look of your blog! What pretty colors!

  6. Robin: I had to look up “grapevine beetle” because I didn’t know what it looked like. Yikes! That would have given me a startle.

    Miss M: Chances are I won’t find all of them, but I will try. They are fast.

    Meemsync: At least now I know what it doing the damage and what to look for (eggs). I hate not knowing.

    EG: Yeah, it’s too bad something so pretty couldn’t be a beneficial insect like ladybugs. Also once they hatch from eggs, before they turn into “cute” beetles, they pile their excrement on their back as a method of self-defense. Yuck!

    Toni: Luckily the three lined potato beetles haven’t done too much harm, so far. Grasshoppers though, those can be detrimental to a crop because there are usually so many of them. Chickens would be so helpful in many ways.

  7. We used to have a heck of a problem with potato beetles when we lived and gardened in central Washington state. The county we lived in was famous for huge factory farm fields of potatoes and there were potato fields close by to our homestead there. Because they used chemical sprays to manage pests - and I did not - the bugs all moved to my garden as a retreat. I almost gave up growing potatoes all together because they would strip the plants down to nothing in short order.

  8. KitsapFG: Oh, that is just horrible. I would have given up trying to grow potatoes in that situation. I have read recently that potatoes can tolerate 20% defoliation without reduction in yield. So far, I still have a manageable amount of potato pests.