Saturday, November 13, 2010

Beet Leaf Miners–The 2010 Insect Of The Year–”Hide n Seek”

I usually regularly rotate vegetables from one area one year, to another area another year. This keeps insects and plant diseases from finding a continuous favorite plant to feed on. This year I grew a batch of beets in an Earth Box planter near an area where I have broken my rotation rule and grown Swiss Chard for a couple of years.  Beet leaf miners were my only insect problem.  You normally can’t see the larva. I split the leaf and coaxed them out.
A small fly lays a batch of small white eggs. You can see them on the underside of the leaf. The tiny eggs hatch and the larva works its way in between the leaf. It mines the leaf as it grows. It separates the layers of the leaf, then it goes back into the soil to again start its life cycle. Beets and swiss chard can be attacked by several generations.  Wood ashes are recommended to add to the soil to make it inhospitable to the larva. I also tried diatomaceous earth. Row covers are also used to keep the fly from finding the newly planted beets. But I avoid row covers since I do not like how they look. Its like not wanting to wear a hat because it will mess up your hair.   But here is my aha moment and observation!
This swiss chard is growing in my window box with nasturtiums and marigolds. They were never found by the beet leaf miner fly. I like to put the upright tropical looking swiss chard in with flowers.
Here is another view of the self-sown marigolds and swiss chard.  I removed all the beets except 1 beet from the Earth Box planter. The one beet was not attacked. Maybe the insect needs several beets to find its target. So this brings me to what I got done this week in the garden: I dug up the raised bed that I used for beets and swiss chard and turned it into a flower bed. I had a bunch of Iris that needed separating and this is where they went. It should be pretty. So next year I will play “hide n hopefully not seek” with the 2010 insect of the year: Beet Leaf Miner


  1. Gloria, I had lots of this damage going on during the summer, but I never knew which insect was doing it!


  2. Leaf miners drive me crazy, especially on our squash, but thankfully, so far, we haven't had them on our beets and chard. We do however grow our greens 'under cover'. I'll be curious to see how your hide-and-seek works. I have read that a trap crop of radishes, near your chard, will help to protect the chard from miners, although I honestly haven't tried it myself. However, radish seeds are very easy to sow, so it might be worth an experiment if hide-and-seek alone isn't sufficient. Good luck!

  3. Could the marigold have discouraged the grub? I always plant marigolds in the veggie garden because someone told me lots of garden pests hate them.

    And on a related note, a beekeeper said he tells people interested in keeping bees not to grow marigolds because it makes dreadful tasting honey.

    Christine in Alaska, marigolds under snow

  4. Hi Eileen - sounds we had the same problem. Next year we will have to compare notes.

  5. Hi Clare - I will try to remember to sow some radish seeds in. I have used them as trap crops for flea beatles. In my beginning garden years flea beetles were regular visitors. The radishes were very successful at catching them. But, now I haven't noticed flea beatles.

  6. Hi Christine - I was also wondering if the marigolds and their insect repelling action were also part of the success. I took some of the dried flowers and sprinkled them into the ex-beet bed. If I remember correctly, I think it is the marigolds roots that repel soil insects. I really do enjoy those short, bright little marigolds.

  7. I have only grown Swiss Chard a few times. This year, I tried one that comes in different colors. They were eaten on all summer. There was never a leaf that I could salvage to eat. I even cut them back to the ground, hoping the new leaves would be left alone, but they weren't. I didn't get close and try to figure out what was eating them. At least my kale was pretty much left alone.

    I'll have to try growing nasturtiums and marigolds around them next year.