Non-sting wasp (cynipoidea) larva
Observation: I was given a picture of unidentified eggs on a plant by the river. The family have never seen these eggs before and was hoping we could identify what the eggs would become at a later stage in life. Is this the a sign of an alien species that could cause an infestation? Do we know what these eggs will become? A. Slakoski, ANTHC
Consult: Alaska Integrated Pest Management (AKIPM), UAF Cooperative Extension Service (Insects and Diseases) Thanks for sharing another great photo! These are not eggs, but they are spiny rose galls or Diplolepis bicolor. They are caused by non-stinging cynipid wasps and their developing larva inside the gall. The gall (plant growth in response to the insect) consists of small hard internal caverns armed with stout, sharp spines on the round exterior. The galls mostly occur on the surface of leaves, but sometimes appear on rose stems. The galls do not appear to harm the plants. Spiny rose gall develops exclusively on wild roses. (There are similar ones on domestic roses.) Many people enjoy photographing and studying these interesting galls.
A major part of exotic pest monitoring is to keep learning what is common or native (even when unusual), so we can quickly distinguish imported or problem pests. Keen observations and good questions, like this, are key element for good monitoring. Corlene Rose, IPM Manager, UAF