Pat from Saint Paul writes
I just noticed quite an infestation of red green galls on my young elm trees, one tree is 12" and the other is 35" around. Is my assessment of the insect correct? The galls seem to mostly be on the tops of the leaves though my research indicates most aphid galls appear on the underside of the leaves? Any complications with the turf under the trees?
We apologize but cannot identify issues with a description. Many galls are caused by insects such as wasps that complete their life cycle on/in the tree, other galls can be caused by disease so determining the cuase of the galls is needed to determine the best treatment plan.
We would recommend consulting with the Master Gardener/Entomologist at your County Extension Office as they are great resource for homeowners. This division of the local university is available for homeowners to assist with disease identification, weed control, soil analysis, active ingredient or product recommendations as well as the best time to apply.
You can find your Master Gardener at this link: http://npic.orst.edu/mgamlr.html
Answer last updated on: 06/06/2022
