Flea Beetles and How To Deal With Them Organically

I noticed that my new potato leaves had little pin holes in them.  The cause is due to flea beetles.  Here is a picture of the pin holes:

Diatomaceous earth is an organic method for killing flea beetles.  I had some on some potatoes I grew in 2008, and they wintered over in the soil and went after my tomato starts in 2009 that I had planted where the potatoes were previously, but this nipped them in the bud right away before they did much damage to the plants.  You can also plant radishes nearby, because they like radishes better than tomatoes.  The beetles go after new growth on the tomatoes and potatoes, so if you get them  covered with the earth right away, the rest of the plant should be fine.  You can get diatomaceous earth at garden centers and some hardware stores.  It is white, and it is best not to breathe this stuff in, and try not to apply it on a windy day or it will blow off the plants.  It’s good to apply it after you have watered when the leaves are a little wet, because it will stick to them better.  However, it does need to be re-applied after rainy weather.  You sprinkle it on the leaves and on the surrounding earth.  It will look like this:

Just thought you might want to know–hope it helps you if you are dealing with this in your plants.



  1. June 22, 2010 at 7:32 pm

    Thanks for visiting my blog. This sounds like some potent stuff. Does it affect the bees, wasp and ladybugs? I have a lot of those kinds of insects and wouldn’t want to kill them too.

    • minervasgardenwriter said,

      June 22, 2010 at 7:46 pm

      Hi Candi: This is information I have about diatomaceous earth: (The short answer is: yes, it will kill bees, and ladybugs and wasps, but read on for more info.) This came from http://www.epinions.com/review/Concern_Diatomaceous_Earth_Crawling_Insect_Killer/content_236400840324
      Diatomaceous Earth is not a normal pesticide since it does not poison insects. It is like very-fine sand, made of the broken up shells of tiny little things called diatomes. Its effect is purely mechanical, rather like sprinkling finely-ground broken glass on your plants. It tends to stick to insects because of tiny electrical charges, like dust sticks to your TV screen. It will cut up any insect that touches it. It is also a drying agent so it will dehydrate them on prolonged contact. Since it is not a poison, insects cannot become immune to it. . . . Diatomaceous Earth will kill just about any bug that crawls. Slugs and snails hate it too. It is no real use against flying pests. Also, it is not too effective against aphids since they hide under the leaves. . . . Diatomaceous Earth has two down sides. First, it washes off with heavy rain. While this is good since it makes it easy to clean up, it does mean that you will have to reapply it if fighting a stubborn infestation. The second problem is that it kills almost anything. While that does make it useful in a wide range of circumstances, you are killing the good bugs with the bad. You may accidentally kill ladybugs that will happily hunt down aphids for you, while allowing the aphids to hide under leaves. Worse, you may kill bees which you need for pollination. Luckily, it is early in the tomato season. Consequently, I did not have to worry about bees at this time. If my tomatoes were bearing flowers, I would have tried to keep the powder on the lower branches away from the flowers.
      Since the plants I am concerned with do not have aphids, I’ve had no ladybugs on them, so it wasn’t an issue about killing ladybugs, which I would not want to do, either. The potato plants also have no flowers at this time, and the garden is surrounded with other flowering plants, so there have been no bees at the potato plants either, so they would not come in contact with the diatomaceous earth.

      Hope this helps clarify a bit.

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