small brow spots on hydrangea

Sylvania, OH

I have a pretty large hydrangea outside my south facing window, and it seems overall to be very heathy. It's beautiful. I'm not sure exactly what kind it is, it was here when I moved in 4 years ago (northwest Ohio zone 6). Today I noticed these tiny brown spots on some of the leaves. it seems to be mainly the leaves facing the window (back of the plant). I did notice what looked like a Colorado potato beetle on one of the leaves (it was kind of skinny and had black and yellow stripes going lengthwise down its body and a red head). I couldn't find any pictures of anything similar or any indication that these beetles eat hydrangeas. It's also not really holes just brown spots. any ideas? I've included a picture of the plant from further back too so you can see its overall condition.

Thumbnail by irukandjia Thumbnail by irukandjia Thumbnail by irukandjia Thumbnail by irukandjia
Contra Costa County, CA(Zone 9b)

When pests are small their tiny mouths cannot crunch through the full thickness of a leaf, so you can see that sort of damage.

Bacterial spot diseases can also do this.

Colorado Potato Beetle seems to favor potatoes and related plants, rarely feeding on plants that are not Solanaceae. Here are some really good pictures. Is this what you saw?
http://entnemdept.ufl.edu/creatures/veg/leaf/potato_beetles.htm

This message was edited Jun 5, 2015 3:31 PM

Sylvania, OH

No. I guess not. I thought it matched another picture I saw. the bug was thinner and it just had a little red head part sticking out. but the yellow and black stripes had the same pattern.

Contra Costa County, CA(Zone 9b)

You might try to ID the pest by googling terms like
Striped beetle
Beetle Ohio
Beetle red head
and other combos.

See if the beetle you saw is a plant eating species, and if it could have done the damage you see.

You can go out at dusk and dawn and see if something is feeding on the leaves. Many plant pests will sleep through the day, often hidden under some mulch or fallen leaves, then come out to eat when it is safer.
You can try to trap bugs with a loosely rolled newspaper on the ground. Shake it into a 5 gallon bucket daily to see what you have caught.

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