elm pouch gall

Elm Insect Duo

I recently looked at some elms on Columbus city streets and took some images of two insects on one leaf, though mostly on lower leafs and trunk sprouts. One insect was a wasp leafminer, Fenusa ulmi.  The larvae of this insect “mine” plant leaf cells for their nutritive value. It is a native insect and generally is worse on non-native elm species and those hybrids with some Asian or European elm genetics. Typically, insecticides are not recommended but labeled systemic insecticides may be useful in situations where applications are warranted.



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Jim Chatfield
Curtis E. Young