Elderberry spindle worms

I recently found out about the pests that have been causing a steady decline in my elderberry bushes. Mines are the ornamental varieties called "black beauty" and "black lace". I haven't seen report on the common elderberry bushes maybe they are resistant to that specific pest.

Three years ago, multiple shoots on one of my elderberries suddenly wilted. I was suspecting a stem borer or fungal infection in the woody part but failed to find any sign. I simply cut down the whole branch. Later on, I kept having one branch after another taken out without finding the cause. This year, I took a close look at the shoots and finally found the culprits. There were borers in the shoots: elderberry spindle worms (Achatodes zeae)!

How stupid was I not checking the flagged shoots in the past few years! And I didn't clean up the diseased tissues and let the pests spread. This time I made sure to kill all the worms and blocked their life cycle. Some more infested branches got stripped bare but I guess it will recover.  

Similar symptoms were found in my peach tree too, caused by oriental fruit moth or other shoot borer. Early detection to destroy the worms is very important to curb the infestation.

I would like to hear what you did to kill the worms and block the life cycle? I have the same problem, and would like to know.
Thanks!
Rebecca

Hi Rebecca, welcome to Permies!

Early detection is the key. Since the bush starts sprouting, I look for any wilting of young shoots. I simply remove the whole shoots and smash the worms. The branch will regrow more shoots quickly.

Since there are lots of wild elderberry around, I get sporadic infestations throughout the season. It's too costly to remove large shoots since they are about to bloom. I try to catch before it's too late by looking for holes at the base of the shoots. Fresh frass outside the hole is seen as the worm is eating through the pith. I squeeze along the stem to kill the worm. Maybe running a razor blade vertically would work too. If there is no new frass it means the worm is dead and the shoot is saved.

Hope it helps and good luck with your tree.

Thank you! This was incredibly helpful. I really appreciate the response. The pictures helped, and I can id the infested areas now. Thanks again!
rca

I have two proven winners black lace elderberries. One has stunted growth. The other seems to be doing ok. Don’t know what is going on. I will try to cut one branch off to see if I can spot any borers. Looking at pictures previously posted will give me a good idea of what to look for.

For me the spindle worm damage only happens in early spring. To prevent it, maybe a black light bug lamp will be effective to catch the moths early before they deposit the eggs.

I have both black lace and black beauty elderberries for cross pollination. Some how the black beauty one has health issues and keeps dying off. The black lace is vigorous and grew from a 4" starter to 6 ft tall bush in a few years.