Thursday, August 23, 2012

Coolest discovery this summer...

Being a lazy gardener paid off this summer with an amazing discovery.  Several weeks ago I noticed that one of my dahlias was getting powdery mildew really bad.  I was going to spray it with a baking soda/water mixture, but kept putting it off.  Then all the leaves were covered in the thick white mildew.  I was going to cut the whole thing back to the ground, but I didn't get around to it.  Then, whole sections of the dahlia starting splitting out and flopping on the ground because I never took the time to stake the thing.  So, I finally got sick of how horrible it looked and decided to do some pruning to cut off the sections that were laying on the ground.

Dahlia covered in powdery mildew (not very pretty!)

While pruning I noticed these little insects all over the leaves that looked like tiny lady bug larvae.  However they were white and not the typical black and orange.  Since lady bugs are good, I was conservative with my pruning.  A couple days later I noticed that the powdery mildew was disappearing and the larvae were clustering around the worst of the powdery mildew.  I was shocked.  I googled around and found that there are many different kinds of lady bugs and some eat fungus.  I couldn't believe it, I had never heard of such a thing before.  It took awhile to find out what type we have, but I'm pretty sure it's a tiny lady bug called the twenty-spotted lady bug (Psyllobora vigintimaculata).

You can see the adult twenty-spotted ladybug in the lower left corner.

I'm so amazed by these little guys.  It's a miracle how the powdery mildew has diminished significantly.     We even moved some of the larvae onto our squash plants to see if they'll help control the powdery mildew there.  We definitely have plenty of it for them to eat.  Now I if can only get some regular lady bug larvae to help control the black aphids around here.  

1 comment:

  1. nice...kinda grody :) but bugs can be great. I haven't really had much problem with mildew this year, I've got both regular zukes and patty pan and dahlias but I've only had one leaf recently show signs. figure thats pretty good. (im in pretty close to you:)