By Paulsner
New Mexico,
United States 
I have a "fruitless plum tree" (has some, but few fruits) in my garden in a semi-arid climate (Albuquerque). The tree appears healthy, but sheds a sticky sap from the foliage that is making a mess on my patio. I have to wash my patio, umbrella, furniture, every week with soapy water and a brush. Is this normal? Is there anything that can be done about it?
17 Oct, 2010
Answers
Sounds as though an aphid is feeding on the leaves. Aphids exude a sugary liquid (honeydew), which collects on the leaves below. You may find, too, that a dark mould forms on the upper surfaces of the leaves. If so, that's 'sooty mould' which forms on the honeydew, and a clear indication of the presence of aphids. Phil J
18 Oct, 2010
Does the tree have a suitable pollinator nearby? This would be another plum that flowers at the same time. Are there plenty of insects around when it is in flower!
18 Oct, 2010