Sunday, December 27, 2009

Squash Lady Beetle





Almost all ladybugs are beneficial to humans. This comes from their preferred food source of aphids and other harmful soft bodied insects that feed on our vegetables, fruits and flowers. Ladybugs are known to consume large amounts of these pests, making them a gardeners best friend. Now I want to introduce you to one of the exceptions to the rule when it comes to lady beetles. This gorgeous spotted ladybug is the Squash Lady Beetle (Epilachna borealis). Instead of feeding on insects, they feed on cucurbit crops, like squash, melons, and cucumbers. As you can see pictured here, they will use their mouths to cut into the stems of the plants and releasing the tasty juices within. In large enough numbers these beetles could cause significant damage to your garden crops. These beetles will show up on your plants in mid-summer. They mate and lay eggs. It isn't long before the eggs hatch and the young are unleashed on your prized cantaloupe. A curious habitat that the adults possess is to circle a potential feeding site, much like a dog goes in circles before lying down for a nap. It is not fully understood what purpose this serves, but it is cute to watch. In the second picture you can see the damage being done to the leaves by their feeding habits.





The young larvae look like spiny little aliens. They are bright yellow and covered with a spattering of black spiny hairs. They will grow quickly and pupate, then the bright orange and black spotted adults will appear. They are one of the largest lady beetles in Eastern North America where they range. Very little is known about their life cycle, or at least very little is reported on it. My mother had a volunteer pumpkin vine show up in her back yard. She left it to grow because she found the leaves to be interesting and beautiful. It produced one pumpkin and dozens of these beetles, in all stages of development.



How ironic is the 2nd & 3rd pictures, notice the aphids that are present?

8 comments:

  1. This post really contains information I can use! I thought all ladybugs were beneficial for the garden. I grew a bunch of cucurbits this year, squash & cukes mostly, and I don't recall seeing any damage patterns quite like this -- but then, I definitely wasn't keeping an eye out for these beetles and their spiny babies.

    Thanks for teaching me something new. :)

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  2. I'm so glad you found some useful info here. Even though these beetles feed on cucurbits, the damage should be minimal unless you have a huge infestation. I can't help but like these little ladybugs and don't mind sharing the garden with them. They are so pretty to look at. Their young are so unique and such a lovely shade of yellow that I am can't help but smile when I find them. If they begin causing any damage I would say removing them by hand or possibly using Sevin Dust should help. Have a Happy New Meredith.

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  3. Great post! I haven't seen them in the garden in the past, but will look this year!

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  4. I had these beetles in my garden last summer. Thought they were lady bugs and heard they were beneficial to the garden so I didn't think twice about them. Then after about a month my zucchini plants and cucumbers were infested with them and their larvae. Didn't take long before both plants were destroyed. I wish I had known what they were earlier as I could've gotten a handle on them. This year I am prepared! Thanks so much for this post.

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  5. It is funny that there could be harmful ladybugs, we are so programed to think all ladybugs are helpful. This darling is one of the exceptions. It is a pretty beetle though.

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  6. okay, but how do you get rid of them????

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  7. I would try sevin dust, it would be the safest thing to use and usually works to keep most things at bay. You will have to reuse it each time it rains though.

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  8. Thank you for the great pics. Those are EXACTLY what I found on my squash plants today! I found only one adult (have hand-picked a few previously but didn't realize what the young form of the adult looked like). I ended up hand-picking (and squshing-BLECH) the foul little things off. I'm hopeful that a few days of diligent destruction on my part with stop the destruction on their part. Thank you again for helping me ID the voracious little buggers!

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