Friday, July 25, 2014

Attack of the Dogwood Sawflies

Look at them, trying to fool me into thinking they are innocent bird droppings!  I'm on to them now, so there's no point in them burying their heads in their bellies and acting innocent.  These are some greedy, greedy bugs.  

Periodically this summer I noticed chewed leaves on my silky dogwood shrubs, but I wasn't really worried about it because one of the perks of having native landscaping his having lots of insects to enjoy, and native plants are tough, and I have a lot.  But yesterday, as I stopped to admire the dogwood fruits, which are a pretty dark blue, I really looked at the shrubs and realized that I don't just have just a few chewed up leaves anymore, I have a full on invasion!  Something is eating them, and it's eating them down to the stems! 

It didn't take much sleuthing to identify the problem.  Can you see the white caterpillar with yellow legs munching a leaf, and the bits of white debris hanging from the leaves?  I have dogwood sawflies, probably Macremphytus tarsatus, if my hasty internet bug identification skills are in working order.  

I think all these little white cases hanging on the stems and leaves are the shed skins as they pupate.  So not only are these greedy bugs, they are messy bugs too, and leave their old clothes laying around.  Dogwood sawflies are native to this area, which doesn't really make me feel any better about the destruction of my dogwoods.  And the adults aren't even pretty butterflies, but instead look like a small brown wasp with white tips on the antenna.  At least they don't sting.  

The frilly looking row of shrubs along the fence behind Mrs. Hall is all silky dogwood.  They aren't supposed to be frilly, and normally they are a dense green wall that blocks all light from my blackberry plants in the evenings.  And just think, I was just complaining about the poor performance of the blackberries and blaming the shade.  Now I have junk blackberries, and the sawflies are eating my shade!  

Helen and Mrs. Hall commiserated with me as I examined the extent of the damage.  We went to the back fence, behind the tangle of garden to see how the little shrub that volunteered all on it's own, from the buried dogwood stems I used in the garden, was doing.  All that's left is a stick with few branches!  Mrs. Hall was very upset, but Helen was just plain mad.  They tried to tell me that it may be time to do something to fight back.  I'm taking this advise into consideration.  


listener said...

We have them too. I make a container of soapy water, put on a pair of "doctor's gloves" and set to work picking them off and popping them into the container. If a leaf has numerous caterpillars on it (usually on the underside), I pluck off the whole leaf and immerse it. The key is to watch for them (here from early July on) and stay ahead of the destruction. Once they stop their cycle, you get a break. Usually in August. I appreciated your well-written story. All the best! :-)

listener said...

Oh, and check the ground around the bush, too. Sometimes they fall off a leaf and curl up; but after awhile they uncurl and crawl straight for the bush and up to a leaf. How they know which way the bush is eludes me, but it's what they do for a living. I have also sometimes found a shiny, reddish, squarish thing stuck under a leaf. I don't yet know if this is a colony of caterpillars soon to hatch, a chrysalis of sorts, or some other species. But just incase I always remove it, since it clearly didn't come with the bush. All good luck!

rain said...

Thanks for the advise Listener. This year, they are even worse than last! I didn't take any action though, and the shrubs are completely naked. This will be a test to see if they can recover. I noticed the caterpillars patrolling the garden looking for a meal now that the dogwood leaves are gone. They don't seem interested in eating anything else, thankfully. But the chickens don't seem interested in eating them, either. I'll keep my eyes out for the shiny squarish red things, too.

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