Leaf horns?

[AW4130]

Any of you peeps out there seen this before or know what this is? Not the leaf, the horn lookin things on it. Because this is the second group of them we've seen this week... On two different species...

 

[Zale]

Whatever you do, do not touch the leaf with your bare hand. Nasty rash could develop. Just kidding. Gall formation caused by an insect. Could be wasp or fly.

 

[BC WetCoast]

Not on that leaf, but pear trellis rust causes similar growths on leaves. This rust has alternate hosts, pear trees and juniper bushes.

 

[AW4130]

Cool thanks guys! Really interesting growth. Never seen it before and had me perplexed! Haha

 

[Zale]

If you cut them open, there is a chance the larva will be present.

 

[old_soul]

Always wondered what those were.....very common on wild cherry trees around here.

 

[Groundman One]

We see them a lot on maple trees here, but smaller in size and more numerous per leaf.

Sorry, lousy pic: http://ohioline.osu.edu/hyg-fact/2000/images/2004_2.jpg

 

[treeseer]

Call em horns if you want, but a more benign common name is nipple gall. The wasps are beneficial associates in the ecosystem.

 

[Zale]

Heh, heh, he said nipple.