Hello Peggy!

I'd be happy to help you.  I'm wondering if you could post some pictures of your elderberries and the bugs.  If you could do some full length of the plants and then as close to the bugs as you can while keeping the photo clear would be super helpful.

Leggy plants is usually a light issue and can also affect fruiting though that could be affected by something else as well. Here's a few resources on growing elderberries.  One option might be to try to move the plants to a better location if you have that ability.  They will do best in full sun which is typically about 6 hrs minimum of direct sun a day.  They can handle a little less than that but if they are in a full shade or mostly shade location, they will struggle. Suckering them is a good practice which it sounds like you already do! 

https://extension.unh.edu/blog/2020/08/what-best-way-grow-elderberries
https://extension.usu.edu/yardandgarden/research/elderberry-in-the-garden

You can also do a soil test to see if there are any nutrient issues contributing to the plant growth and lack of fruiting.  UVM has a great resource for this!

https://www.uvm.edu/extension/agricultural-and-environmental-testing-lab

As for the bugs, I've looked at some insects that are common on Elderberry but none seem to match that description so a photo would be super helpful.

I hope this helps and let me know if you'd like to continue this conversation about the bugs or if you have any other questions.

Thank you for reaching out to the help line!

Best wishes!