Thursday, August 14, 2008

The Million Caterpillar Army

Sawflies have pretty much defoliated my wonderful little river birch. Just look at the tree!! I planted this little guy two years ago as a six foot tall sapling, it is now about 12 feet tall and very full-or should be. I kept seeing the leaves disappear, but try as I might I could not find the culprits. That is until I got really desperate just knowing my little birch would be no more if I did not take action.
On one sultry morning I decided to look real hard for the bad, bad pest. I even picked a leaf that still had some leaf on it (this is where the boogers were) and brought it closer to my eyes-poor eyesight you see. Obviously I must have poor eyesight since it took me so long to find the million caterpillar army! That is my story and I'm sticking to it! Can you see the little squad of the pests all lined up munching away on this leaf?
Look, here is the rest of the platoon going to town on a leaf still on the tree! It is characteristic of sawfly larvae to arch up into an S-shape when disturbed. They were seriously disturbed on this fateful day. I am not abashed in saying so-I won the war! Disclaimer: Yes! All of these sawfly larvae perished!
This handy bottle of a botanical insecticide helped me out. I was ever so happy I had it on hand. Normally I do not use insecticides with the exception of Sevin dust on my zucchini and broccoli plants. Sevin dust would've worked well but could you just see me up on my ladder sprinkling the white dust all over the million caterpillar army? Nope, me neither. I tried this spray and it worked wonders! Its main ingredient is a pyrethrin; which is a natural substance, though still dangerous if not used in the manner intended. I learned all about this insecticide in my pesticide class at Nashville State Community College (NSCC) and really do appreciate the information. I only had it on hand for pesky houseplant bugs but it worked well on these sawfly larva as well.

The spray was easy to use (make sure to use on a calm day) and took care of the million caterpillar army within about 15 minutes. Yup, they were not killed outright, but die they did.

The poor birch will not re-grow its lost leaves, but will continue to grow new ones at the tip of the branches and it will recover. I have resolved to use Bayer Advanced Tree and Shrub Care systemic insecticide on this tree in the future. That insecticide is reputed to last more than one year. I try to garden totally organically, but sometimes I just have to take action to save prized plants in the garden while weighing the risks and benefits of my actions. Let me tell all you gardeners, Japanese beetles have NOTHING on these sawfly larva and they are bad!

On a good note, the following insect is a welcomed visitor to my garden. The 'parsley' caterpillars have finally arrived! Thank goodness they are not pests and I have no problem with them eating my parsley and Bishops weed (which is where I found this fella).in the garden....hoping my birch tree recovers soon.


  1. The million caterpillar army is a great description...I am sorry they marched on your tree! Is birch their favorite snack? Have you noticed many cicadas?

    I report from the field that there are no swallowtail caterpillars on my parsley or fennel! Where are they? It's time for them to show up!


  2. Good morning Gail. You are an early bird! There are many types of sawflies, all mainly named for the tree they feed upon. This is the birch sawfly, but they also feed on spruce, rose, pear and pines. It is interesting the mama fly actually lays the eggs in the leaf margin where the boogers hatch and feed voraciously. They are bad. I don't know where your parsley caterpillars are at all! I have had them for over two weeks now. They were late this year but should be around. Check your bishops weed too. Dill maybe? I hope they show up soon.

  3. Thanks for an informative, if rather unappetizing, post this morning (I hate worms!). It's good to know there are some safe insect sprays you can use without feeling guilty. I am like you, though; if something is really endangering a plant--especially a tree--I will use chemicals! I wouldn't have had any qualms about chemical warfare with this army:)

  4. Great post today Tina. I've used Bayer Advanced Rose Care systemic. It works really well at keeping Blackspot at bay. I love the caterpillars that are on your parsley!

  5. Mom you MURDER! Just kidding! Even as animal and bug friendly as I am I would have killed them as well.
    Compost is doing great and is no longer locked in the bathroom and IS sharing the litter boxes with the other kitties in my house, though none of the cats are allowed in the bedroom anymore. Still haven't found her a home, but trying really hard to get Jay to take her for Emma, plus he loves cuddly cats and she is that for sure. Hope she doesn't end up having to go the shelter...

  6. Yuck! I can see why they are called sawflies they saw right in, over and under everything! Glad we don't have them although we have our pest.

  7. Great post Tina. I never knew of these worms. It looks like they could kill a young tree. With no leaves the tree would die, wouldn't it?
    I need to plant some dill to see if I can attract butterflies. The monarch maybe.

  8. Hey Tina. I think the last caterpillar will turn into a swallowtail butterfly.

    Saw flies are a pest. I have them on roses early in the season.

  9. An Icky bug in the garden for sure!

    Surprise, I found a bud on the second jimsonweed plant! I am so excited about that. I will make sure the Saint gets to see this one bloom if I have to take him out to the garden during the night! lol....

    1 inch total rainfall yesterday on our yard! Downtown area had 2 inches. Go figure. Yea, a good start to what I hope is more rain to follow soon.

    It is August in the Deep South and I have the windows to the house open today! Was nice sleeping with them open and fresh air coming in the house. Cats are really enjoying the fun window hopping! LOL… Thank goodness the smell of the paper mill which is many many miles away from us, is finally out of the air! On rainy days the air is perfect for the scent of the mill to float around. My mom was born in LA and loves that smell. Not me, Yuck!

  10. You know I wasn't so sure how this post would be received since so many of us want to be organic, I am happy to see you all agree. This tree was in danger of perishing since it is small and the infestation was so severe.

    Rose, Thanks! Drastic measures were required.

    PG, I just learned about the Bayer stuff this year in a seminar and so far I am a fan. I use it on oaks, azaleas and now this birch. I hope it works from now on. The tree will get too big to spray. This caterpillar has already turned-a post coming on it soon. Love them. You should have some too.

    Christine, Compost is the reason I called you last night. I was wondering the status of her now. I am glad to hear she is doing better. Such a shame it did not work with the other family. Good luck.

    Dawn, The sawfly itself is actually unnoticeable and looks kind of like a bee. They are common even in your area but you may see more pine sawflies than birch. Even on the birch, if the tree is large the damage may not be so noticeable as it was in my case. Pest everywhere.

    Lola, I was really afraid the tree would be completely defoliated and die for sure. It is recovering and has grown new leaves on the tips now. Small trees can die easily with no leaves, no food and stress.They say milkweed and butterfly attract monarchs pretty well. Try those two flowers. I see the butterflies but not the larva.

    Marnie, I read there are rose sawflies. Do they cause you a bunch of damage? They are really awful here. The caterpillar already turned now. A black swallowtail. I shared some with some friends too. Theirs should be turning soon. Love these guys and they can eat away. Parsley being a biennial is going to die out anyhow.

    Skeeter, Just wait, the jimsonweed will come into its own. All it really needs is tons of sun to do well. Yes, take the Saint and make sure he smells it. One inch of rain is good. Lola, did you get about that too? It IS a miracle to have windows opened in the deep south in August. A true blessing.

  11. I'm sorry about your birch! I would have done the same on those caterpillars. It would be easy to guess that it was drought causing your leaves to disappear unless you looked closer. Those little guys aren't welcome!

  12. Wow, they did alot of damage. I didn't know they were called saw worms either, I just thought they were catepillars.

  13. Yikes those are nasty little things. I am glad you found a solution for them(-:

  14. Great detective work, Tina--and I use pyrethrins occasionally (they are made from a kind of daisy, I think, but as you point out, they can be dangerous to other animals). Are you worried about good bugs, though, with the systemic insecticide? Though I guess bees and such arent' that attracted to river birches . . .Anyway, glad you won the war!

  15. Hi Tina, you did the right thing. We had the same problem with one of our birches the first year it was planted. I couldn't see the bug and like you had to really inspect to find them, same guys. I hauled out the sevin and sprayed the whole tree, for it was only about three feet tall then, a cutting from my neighbors. It is a giant now and those pests never returned, thank goodness, for it would not be possible to spray it now. The birches are dropping their leaves like crazy now, same thing happened last year with the dryness. You got rain? None here. ;-< Hooray for your Eastern Swallowtail, we have lots now, they seem to be late this year. They like the bronze fennel, but only one stand of it, by the hedge.

  16. I need to learn more about the diffrents bugs and insects that get on our plants. I know a few but most of the time I have to look them up on the internet to make sure I am not killing off a freindly one. I only use organic products too. Most of the time, all is well, but once in a while I do need to take some sort of action.

    I glad you discoverd the problem and what to do about it.

  17. Dave, They were not welcomed at all and thanks.

    Cindee, Awful little bugs for sure.

    Cosmo, I am glad I won the war too. I don't think a systemic herbicide would hurt bees would it? This is a kind you bury in the ground. Actually, I use it on oaks to take away the gall wasp; which can actually kill oaks. I hope that works. The bees should be ok as I think a bug would have to actually feed on the plant and get the juices somehow, either by eating or drilling. I hope no more of any! Pyrethrins are natural but still dangerous. You are right about the daisy. A daisy that grows in I think South America and is a member of the chrysanthemum family. What do you have to use pyrethrins on? I am so happy to hear others use this too. I just knew I would get some flak for killing these guys but I was wrong.

    Frances, You are always such a big help. I hope I don't get anymore infestations. These bugs must like the little trees. My birch is not dropping leaves and neither are the tulip poplars even though we have had no rain. I have had to water. urrrr! I would love to grow some fennel but don't have it for some reason. Just dill and parsley and now I see the caterpillars like bishops weed. Who would've thought? Not me. The swallowtails are great and today I saw a zebra one! I think they are the state caterpillar (gotta look it up). I couldn't snap a picture-too fast.

    Eve, Bugs are such a part of gardening that they usually don't bother me. But it seems the more you garden the more bugs you meet and don't know so research pays off. I am actually terrible with bugs, and weeds. I never really know what is what but try to live and let live. In this case the birch would've surely died so I had to act. Poor things.

  18. Tina, we had 3 strong hard rains yesterday. Tornado warnings. A much gentler shower this morning. clear now, but could change.

  19. Lola, Lucky you! I wish we would get even a few drops. All is dry. Grass is finally turning brown and crispy. I should not complain though, it has been a super summer so far and we have gotten some rain. Soon enough fall will be here.

  20. We had the windows open for most of the day! Rare thing this time of year so happy for the break on the power bill!!! lol.... Can feel the humidity creeping back so windows closed now... Was a nice 24 hour break!

  21. Yuck!!!! Nasty bug and glad you got rid of em. Christy and Jay came down with Josh and he put on a show and a half. He his getting to be quite the ham. He now says "more, please". So cute. Sarah cut his hair as it was really getting long and everyone thought he was a girl. I guess with those big eyes, long eye lashes and long curls he did sorta look girlish. But Sarah dresses him in such cute boy clothes, I guess most people go by looks and not clothes.

  22. Thanks for the informative post Tina! I have a thriving river birch new this spring, and I'll be watching for those little buggers.

    I work hard at keeping my garden organic, and have even converted my husband to mostly-organic lawn care. I agree there are times when careful use of the big guns is justified.