I wouldn't worry. Robinias have all kinds of borers that do this and the trees still grow to maturity. Leaf miners in the leaves, small brownish beetles that cause leaf drop in July, borers that infect every part. The tree will grow several tops, each in turn dying. You also usually find these trees as twins, that is, 2 trees develop and grow side by side until one falls. Not to worry, when something happens to it, the ground erupts in 100 new trees that grow over your head in 2 years. Did you plant these? The small trees are used extensively for fence posts around here. The flowers are a source of very light colored honey, but the fragility of the raceme of white flowers in May means you don't get a honey crop from Black Locust every year. "Locust Week", when the trees are in bloom, also tends to be a time when spring storms blow the flowers off the tree.

We started seeing it randomly about three or four years ago in select areas over a fifty mile stretch of coastline..which might be more, but outside my service zone. We have pictures of the sap suckers in the tops of young birch, and since the bird is migratory and favors to use the same 'stopping off' spots each year, we've had repeat attacks to the same trees. Since then the problem has increased and a mountain ash tree growing beside a birch won't be bothered, but the birch gets pulverized. Unlike the apples or the ash, the birch can't stand the hole restrictions in the bark so the tops are all starting to die off... The only thing I can imagine is either the bird is arriving earlier then it ever had before, or the former sap-source tree's flow is starting later...either way, there are no records to use as a comparison for timings..

Hi Cooks, Thanks, this article you referenced provides helpful information. The following section in the article has two incorrect words, the words routing should be replaced with the word routine. How to prevent African Violets from suckering? Ensure basic routing care of African Violets to prevent suckering. Keep the plants watered, fertilized and repotted in fresh soil and suckers will not form. Many times, if the suckers are continually removed from the plant, this will also prevent future suckering. Routing grooming of the African Violet plant can ensure that it maintains good crown growth and breaks the habit of suckering. The article states at the end that if a plant has too many large suckers, it is best to get rid of it and replace it. Because the plant is a living organism, it might be kinder to the plant to take leaves to start new plants and allow the parent plant to live. It is also possible to remove larger crowns and restart them so that the original plant may survive and have a second chance. If removing crowns results in a long neck, this can be potted down. This is also good practice for those new to the growing and care of AFs. Joanne

Anyway there is a variable in my system which makes a conclusion impossible: 1. the ENS only has a stem diameter of about 1 cm. The main vine is about 4 cm.